- Field-induced surface hopping (FISH) for the simulation of ultrafast processes in photochemistry and photophysics
- Optimal control of light-induced dynamical processes in complex systems
- Simulation of time- and angle-resolved spectroscopic observables
- Semiclassical methods for coupled electron-nuclear dynamics
Dr. Jens Petersen
Dr. Jens Petersen
Akademischer Rat
+49-(0)931-31-88832
Institut für Physikalische und Theoretische Chemie
Julius-Maximilians Universität Würzburg
Emil-Fischer-Straße 42
97074 Würzburg
Scientific Vita
FU Berlin
July 2013
PhD (Dr. rer. nat.) in Theoretical Physics
Thesis title: “Development of Mixed Quantum-Classical Methods for Coherent Control and Ultrafast Spectroscopy in Complex Systems”, grade: summa cum laude, Supervisors: Prof. Dr. Roland Mitrić (FU Berlin) and Prof. Dr. Dr. h.c. Vlasta Bonačić-Koutecký (HU Berlin)
HU Berlin
March 2008
Diploma in Chemistry
Thesis title: “Laserfeldinduziertes Surface-Hopping zur Analyse und Kontrolle der Mehrzustandsdynamik”, Supervisor: Prof. Dr. Dr. h.c. Vlasta Bonačić-Koutecký,
HU Berlin
2003 - 2008
Studies in Chemistry and Physics
Research Interests
Publications
| 34. | Issler, Kevin; Mitric, Roland; Petersen, Jens A trajectory surface hopping study of the vibration-induced autodetachment dynamics of the 1-nitropropane anion Journal Article Theo. Chem. Acc., 142 , pp. 123, 2023. @article{Issler2023c, title = {A trajectory surface hopping study of the vibration-induced autodetachment dynamics of the 1-nitropropane anion}, author = {Kevin Issler and Roland Mitric and Jens Petersen}, doi = {https://doi.org/10.1007/s00214-023-03063-z}, year = {2023}, date = {2023-11-08}, journal = {Theo. Chem. Acc.}, volume = {142}, pages = {123}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 33. | Issler, Kevin; Mitric, Roland; Petersen, Jens HORTENSIA, a program package for the simulation of nonadiabatic autoionization dynamics in molecules Journal Article J. Chem. Phys., 159 , pp. 134801, 2023. @article{Issler2023b, title = {HORTENSIA, a program package for the simulation of nonadiabatic autoionization dynamics in molecules}, author = {Kevin Issler and Roland Mitric and Jens Petersen}, doi = {https://doi.org/10.1063/5.0167412}, year = {2023}, date = {2023-10-03}, journal = {J. Chem. Phys.}, volume = {159}, pages = {134801}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 32. | Issler, Kevin; Sturm, Floriane; Petersen, Jens; Flock, Marco; Mitric, Roland; Fischer, Ingo; Barreau, Lou; Poisson, Lionel Time-resolved photoelectron spectroscopy of 4-(dimethylamino)benzethyne – an experimental and computational study Journal Article Phys. Chem. Chem. Phys., 25 , pp. 9837-9845, 2023. @article{Issler2023, title = {Time-resolved photoelectron spectroscopy of 4-(dimethylamino)benzethyne – an experimental and computational study}, author = {Kevin Issler and Floriane Sturm and Jens Petersen and Marco Flock and Roland Mitric and Ingo Fischer and Lou Barreau and Lionel Poisson}, doi = {https://doi.org/10.1039/D3CP00309D}, year = {2023}, date = {2023-03-27}, journal = {Phys. Chem. Chem. Phys.}, volume = {25}, pages = {9837-9845}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 31. | Kirst, Christin; Knechtel, Fabian; Gensler, Manuel; Fischermeier, David; Petersen, Jens; Danaf, Nader A; Tietze, Jonathan; Wedel, Armin; Lamb, Don C; Mitrić, Roland; Karaghiosoff, Konstantin Aggregation-Induced Emission in a Flexible Phosphine Oxide and its Zn(II) Complexes—A Simple Approach to Blue Luminescent Materials Journal Article Adv. Funct. Mater., 33 , pp. 2212436, 2023. @article{Kirst2023, title = {Aggregation-Induced Emission in a Flexible Phosphine Oxide and its Zn(II) Complexes—A Simple Approach to Blue Luminescent Materials}, author = {Christin Kirst and Fabian Knechtel and Manuel Gensler and David Fischermeier and Jens Petersen and Nader A. Danaf and Jonathan Tietze and Armin Wedel and Don C. Lamb and Roland Mitrić and Konstantin Karaghiosoff}, doi = {https://doi.org/10.1002/adfm.202212436}, year = {2023}, date = {2023-01-24}, journal = {Adv. Funct. Mater.}, volume = {33}, pages = {2212436}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 30. | Issler, Kevin; Mitric, Roland; Petersen, Jens Quantum-classical Dynamics of Vibration-Induced Autoionization in Molecules Journal Article J. Chem. Phys., 158 , pp. 034107, 2023. @article{Issler2022, title = {Quantum-classical Dynamics of Vibration-Induced Autoionization in Molecules}, author = {Kevin Issler and Roland Mitric and Jens Petersen}, doi = {10.1063/5.0135392}, year = {2023}, date = {2023-01-19}, journal = {J. Chem. Phys.}, volume = {158}, pages = {034107}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 29. | Petersen, J; Einsele, R; Mitric, R On the quantum and classical control of laser-driven isomerization in the Wigner representation Journal Article J. Chem. Phys. , 154 , pp. 174103, 2021. @article{petersen_2021, title = {On the quantum and classical control of laser-driven isomerization in the Wigner representation}, author = {J. Petersen and R. Einsele and R. Mitric}, url = {https://aip.scitation.org/doi/full/10.1063/5.0046030}, doi = {10.1063/5.0046030}, year = {2021}, date = {2021-05-04}, journal = {J. Chem. Phys. }, volume = {154}, pages = {174103}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 28. | Hirsch, Florian; Pachner, Kai; Fischer, Ingo; Issler, Kevin; Petersen, Jens; Mitric, Roland; Bakels, Sjors; Rijs, Anouk Do Xylylenes isomerize in Pyrolysis? Journal Article ChemPhysChem, 21 (14), pp. 1515-1518, 2020. @article{isslerk_2020_05_06, title = {Do Xylylenes isomerize in Pyrolysis?}, author = {Florian Hirsch and Kai Pachner and Ingo Fischer and Kevin Issler and Jens Petersen and Roland Mitric and Sjors Bakels and Anouk Rijs}, url = {https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cphc.202000317}, doi = {10.1002/cphc.202000317}, year = {2020}, date = {2020-06-05}, journal = {ChemPhysChem}, volume = {21}, number = {14}, pages = {1515-1518}, abstract = {A gas phase IR spectrum of para‐xylylene was recorded by IR/UV ion dip spectroscopy. The molecule was generated by flash pyrolysis. Ortho‐ and meta‐xylylene partially rearrange to benzocyclobutene and styrene. Their detection can be explained by the oscillator strength of the UV transition.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A gas phase IR spectrum of para‐xylylene was recorded by IR/UV ion dip spectroscopy. The molecule was generated by flash pyrolysis. Ortho‐ and meta‐xylylene partially rearrange to benzocyclobutene and styrene. Their detection can be explained by the oscillator strength of the UV transition. |
| 27. | Röder, Anja; Petersen, Jens; Issler, Kevin; Fischer, Ingo; Mitric, Roland; Poisson, Lionel J. Phys. Chem. A, 123 (50), pp. 10643-10662, 2019. @article{feature_jpca_19, title = {Exploring the Excited-State Dynamics of Hydrocarbon Radicals, Biradicals and Carbenes Using Time-Resolved Photoelectron Spectroscopy and Field-Induced Surface Hopping Simulations}, author = {Anja Röder and Jens Petersen and Kevin Issler and Ingo Fischer and Roland Mitric and Lionel Poisson}, doi = {10.1021/acs.jpca.9b06346}, year = {2019}, date = {2019-09-05}, journal = {J. Phys. Chem. A}, volume = {123}, number = {50}, pages = {10643-10662}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 26. | Issler, K; Röder, A; Hirsch, F; Poisson, L; Fischer, I; Mitric, R; Petersen, J Excited state dynamics and time-resolved photoelectron spectroscopy of para-xylylene Journal Article Faraday. Discuss., 212 , pp. 83-100, 2018. @article{issler2018a, title = {Excited state dynamics and time-resolved photoelectron spectroscopy of para-xylylene}, author = {K Issler and A Röder and F Hirsch and L Poisson and I Fischer and R Mitric and J Petersen}, url = {http://pubs.rsc.org/en/content/articlelanding/2018/fd/c8fd00083b#!divAbstract}, year = {2018}, date = {2018-05-08}, journal = {Faraday. Discuss.}, volume = {212}, pages = {83-100}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 25. | Petersen, J; Lindner, J; R., Mitric Ultrafast Photodynamics of Glucose Journal Article J. Phys. Chem. B, 122 , pp. 19-27, 2018. @article{petersen2018a, title = {Ultrafast Photodynamics of Glucose}, author = {J Petersen and J Lindner and Mitric R.}, url = {http://dx.doi.org/10.1021/acs.jpcb.7b08602}, year = {2018}, date = {2018-01-01}, journal = {J. Phys. Chem. B}, volume = {122}, pages = {19-27}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 24. | Roeder, Anja; Issler, Kevin; Poisson, Lionel; Humeniuk, Alexander; Wohlgemuth, Matthias; Comte, Michel; Lepetit, Fabien; Fischer, Ingo; Mitric, Roland; Petersen, Jens. Femtosecond dynamics of the 2-methylallyl radical: A computational and experimental study. Journal Article Journal of Chemical Physics, 147 , pp. 013902, 2017. @article{Roeder2017, title = {Femtosecond dynamics of the 2-methylallyl radical: A computational and experimental study.}, author = {Anja Roeder and Kevin Issler and Lionel Poisson and Alexander Humeniuk and Matthias Wohlgemuth and Michel Comte and Fabien Lepetit and Ingo Fischer and Roland Mitric and Jens. Petersen}, url = {http://doi.org/10.1063/1.4974150}, doi = {10.1063/1.4974150}, year = {2017}, date = {2017-02-02}, journal = {Journal of Chemical Physics}, volume = {147}, pages = {013902}, publisher = {American Institute of Physics}, abstract = {We investigate the photodynamics of the 2-methylallyl radical by femtosecond time-resolved photoelectron imaging. The expts. are accompanied by field-induced surface hopping dynamics calcns. and the simulation of time-resolved photoelectron intensities and anisotropies, giving insight into the photochem. and nonradiative relaxation of the radical. 2-methylallyl is excited at 236 nm, 238 nm, and 240.6 nm into a 3p Rydberg state, and the subsequent dynamics is probed by multiphoton ionization using photons of 800 nm. The photoelectron image exhibits a prominent band with considerable anisotropy, which is compatible with the result of theory. The simulations show that the initially excited 3p state is rapidly depopulated to a 3s Rydberg state, from which photoelectrons of high anisotropy are produced. The 3s state then decays within several 100 fs to the D1 (n$pi$) state, followed by the deactivation of the D1 to the electronic ground state on the ps time scale. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } We investigate the photodynamics of the 2-methylallyl radical by femtosecond time-resolved photoelectron imaging. The expts. are accompanied by field-induced surface hopping dynamics calcns. and the simulation of time-resolved photoelectron intensities and anisotropies, giving insight into the photochem. and nonradiative relaxation of the radical. 2-methylallyl is excited at 236 nm, 238 nm, and 240.6 nm into a 3p Rydberg state, and the subsequent dynamics is probed by multiphoton ionization using photons of 800 nm. The photoelectron image exhibits a prominent band with considerable anisotropy, which is compatible with the result of theory. The simulations show that the initially excited 3p state is rapidly depopulated to a 3s Rydberg state, from which photoelectrons of high anisotropy are produced. The 3s state then decays within several 100 fs to the D1 (n$pi$) state, followed by the deactivation of the D1 to the electronic ground state on the ps time scale. [on SciFinder(R)] |
| 23. | Gerbich, Thiemo; Schmitt, Hans-Christian; Fischer, Ingo; Mitric, Roland; Petersen, Jens. Dynamics of Isolated 1,8-Naphthalimide and N-Methyl-1,8-naphthalimide: An Experimental and Computational Study. Journal Article Journal of Physical Chemistry A, 120 (13), pp. 2089–2095, 2016, ISSN: 1089-5639. @article{Gerbich2016, title = {Dynamics of Isolated 1,8-Naphthalimide and N-Methyl-1,8-naphthalimide: An Experimental and Computational Study.}, author = {Thiemo Gerbich and Hans-Christian Schmitt and Ingo Fischer and Roland Mitric and Jens. Petersen}, doi = {10.1021/acs.jpca.6b01226}, issn = {1089-5639}, year = {2016}, date = {2016-01-01}, journal = {Journal of Physical Chemistry A}, volume = {120}, number = {13}, pages = {2089--2095}, publisher = {American Chemical Society}, abstract = {The excited-state structures and dynamics of 1,8-naphthalimide (NI) and N-methyl-1,8-naphthalimide (Me-NI) have been studied in the gas phase by picosecond time- and frequency-resolved multiphoton ionization spectroscopy. The energies of several electronically excited singlet and triplet states and the S1 vibrational wavenumbers were calcd. Nonadiabatic dynamics simulations support the anal. of the radiationless deactivation processes. The origin of the S1 ← S0 ($pi$$pi$*) transition was found at 30,082 cm-1 for NI and at 29,920 cm-1 for Me-NI. Furthermore, a couple of low-lying vibrational bands were resolved in the spectra of both mols. In the time-resolved scans a biexponential decay was apparent for both Me-NI and NI. The fast time const. is in the range of 10-20 ps, whereas the second one is in the nanosecond range. In accordance with the dynamics simulations, intersystem crossing to the fourth triplet state S1 ($pi$$pi$*) → T4 (n$pi$*) is the main deactivation process for Me-NI due to a large spin-orbit coupling between these states. Only for significant vibrational excitation internal conversion via a conical intersection becomes a relevant deactivation pathway. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } The excited-state structures and dynamics of 1,8-naphthalimide (NI) and N-methyl-1,8-naphthalimide (Me-NI) have been studied in the gas phase by picosecond time- and frequency-resolved multiphoton ionization spectroscopy. The energies of several electronically excited singlet and triplet states and the S1 vibrational wavenumbers were calcd. Nonadiabatic dynamics simulations support the anal. of the radiationless deactivation processes. The origin of the S1 ← S0 ($pi$$pi$*) transition was found at 30,082 cm-1 for NI and at 29,920 cm-1 for Me-NI. Furthermore, a couple of low-lying vibrational bands were resolved in the spectra of both mols. In the time-resolved scans a biexponential decay was apparent for both Me-NI and NI. The fast time const. is in the range of 10-20 ps, whereas the second one is in the nanosecond range. In accordance with the dynamics simulations, intersystem crossing to the fourth triplet state S1 ($pi$$pi$*) → T4 (n$pi$*) is the main deactivation process for Me-NI due to a large spin-orbit coupling between these states. Only for significant vibrational excitation internal conversion via a conical intersection becomes a relevant deactivation pathway. [on SciFinder(R)] |
| 22. | Röhr, Merle I S; Mitric, Roland; Petersen, Jens. Vibrationally resolved optical spectra and ultrafast electronic relaxation dynamics of diamantane. Journal Article Physical Chemistry Chemical Physics, 18 (12), pp. 8701–8709, 2016, ISSN: 1463-9076. @article{Röhr2016a, title = {Vibrationally resolved optical spectra and ultrafast electronic relaxation dynamics of diamantane.}, author = {Merle I S Röhr and Roland Mitric and Jens. Petersen}, doi = {10.1039/C6CP00137H}, issn = {1463-9076}, year = {2016}, date = {2016-01-01}, journal = {Physical Chemistry Chemical Physics}, volume = {18}, number = {12}, pages = {8701--8709}, publisher = {Royal Society of Chemistry}, abstract = {We present theor. simulations of the vibrationally resolved photoabsorption and photoemission spectra of diamantane combined with nonadiabatic dynamics simulations in order to identify the state responsible for the measured photoluminescence of diamantane and to det. the mechanism and the time-scales of the electronic state relaxation. Diamantane is a prototype representative of the diamondoid class of hydrocarbons which have recently gained significant interest due to their unique electronic properties. This mol. is characterized by an almost dark first excited state, which therefore cannot be directly excited. Moreover, the calcd. vertical transition from the geometrically relaxed first excited state to the ground state also bears no intensity. However, recent expts. suggest that the obsd. photoluminescence originates from the lowest excited state. We have performed spectral simulations in the frame of the Herzberg-Teller approxn. for vibronic transitions, which goes beyond the Franck-Condon approxn. of const. transition dipole moments and takes into account their linear dependence on the geometrical deformations. In this way, the available exptl. spectrum could be fully reproduced, resolving the issue about the origin of the photoluminescence. Moreover, the photoemission from the first excited state also implies that ultrafast nonradiative processes have to take place after the initial excitation of the bright electronic states. We have detd. the mechanism and time-scales of these relaxation processes by performing nonadiabatic dynamics simulations in the manifold of s- and p-type Rydberg excited states. The simulations demonstrate that the lowest excited electronic state of diamantane gains significant population from higher-lying states already after several hundreds of femtoseconds. Thus, our dynamics simulations combined with spectra calcd. using the Herzberg-Teller approxn. allow us to fully explain the obsd. photoabsorption and photoemission properties of diamantane. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } We present theor. simulations of the vibrationally resolved photoabsorption and photoemission spectra of diamantane combined with nonadiabatic dynamics simulations in order to identify the state responsible for the measured photoluminescence of diamantane and to det. the mechanism and the time-scales of the electronic state relaxation. Diamantane is a prototype representative of the diamondoid class of hydrocarbons which have recently gained significant interest due to their unique electronic properties. This mol. is characterized by an almost dark first excited state, which therefore cannot be directly excited. Moreover, the calcd. vertical transition from the geometrically relaxed first excited state to the ground state also bears no intensity. However, recent expts. suggest that the obsd. photoluminescence originates from the lowest excited state. We have performed spectral simulations in the frame of the Herzberg-Teller approxn. for vibronic transitions, which goes beyond the Franck-Condon approxn. of const. transition dipole moments and takes into account their linear dependence on the geometrical deformations. In this way, the available exptl. spectrum could be fully reproduced, resolving the issue about the origin of the photoluminescence. Moreover, the photoemission from the first excited state also implies that ultrafast nonradiative processes have to take place after the initial excitation of the bright electronic states. We have detd. the mechanism and time-scales of these relaxation processes by performing nonadiabatic dynamics simulations in the manifold of s- and p-type Rydberg excited states. The simulations demonstrate that the lowest excited electronic state of diamantane gains significant population from higher-lying states already after several hundreds of femtoseconds. Thus, our dynamics simulations combined with spectra calcd. using the Herzberg-Teller approxn. allow us to fully explain the obsd. photoabsorption and photoemission properties of diamantane. [on SciFinder(R)] |
| 21. | Gerbich, Thiemo; Schmitt, Hans-Christian; Fischer, Ingo; Petersen, Jens; Albert, Julian; Mitric, Roland. Time-Resolved Study of 1,8-Naphthalic Anhydride and 1,4,5,8-Naphthalene-tetracarboxylic Dianhydride. Journal Article Journal of Physical Chemistry A, 119 (23), pp. 6006–6016, 2015, ISSN: 1089-5639. @article{Gerbich2015, title = {Time-Resolved Study of 1,8-Naphthalic Anhydride and 1,4,5,8-Naphthalene-tetracarboxylic Dianhydride.}, author = {Thiemo Gerbich and Hans-Christian Schmitt and Ingo Fischer and Jens Petersen and Julian Albert and Roland. Mitric}, doi = {10.1021/jp511843q}, issn = {1089-5639}, year = {2015}, date = {2015-01-01}, journal = {Journal of Physical Chemistry A}, volume = {119}, number = {23}, pages = {6006--6016}, publisher = {American Chemical Society}, abstract = {We investigate the excited electronic states of 1,8-naphthalic anhydride (NDCA) and 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA) by time- and frequency-resolved electronic spectroscopy in the gas phase using picosecond lasers and by femtosecond time-resolved transient absorption in cyclohexane. The expts. are accompanied by calcns. that yield the energy of the excited singlet and triplet states as well as by surface hopping dynamics simulations and calcns. of spin-orbit couplings that give insight into the photochem. The origin of the A 1A1 ← X 1A1 ($pi$$pi$*) transition in isolated NDCA was found at 30 260 cm-1, and several low-lying vibrational bands were obsd. The lifetime drops sharply from 1.2 ns at the origin to around 30 ps at an excess energy of 800 cm-1. Both internal conversion (IC) and intersystem crossing (ISC) are possible deactivation pathways as found in coupled electron-nuclear dynamics simulations. In cyclohexane soln., two time consts. were obsd. Deactivation of the initially excited state by ISC seems to dominate as supported by computations. For NTCDA we obsd. a gas phase lifetime of 16 ps upon excitation at 351 nm. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } We investigate the excited electronic states of 1,8-naphthalic anhydride (NDCA) and 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA) by time- and frequency-resolved electronic spectroscopy in the gas phase using picosecond lasers and by femtosecond time-resolved transient absorption in cyclohexane. The expts. are accompanied by calcns. that yield the energy of the excited singlet and triplet states as well as by surface hopping dynamics simulations and calcns. of spin-orbit couplings that give insight into the photochem. The origin of the A 1A1 ← X 1A1 ($pi$$pi$*) transition in isolated NDCA was found at 30 260 cm-1, and several low-lying vibrational bands were obsd. The lifetime drops sharply from 1.2 ns at the origin to around 30 ps at an excess energy of 800 cm-1. Both internal conversion (IC) and intersystem crossing (ISC) are possible deactivation pathways as found in coupled electron-nuclear dynamics simulations. In cyclohexane soln., two time consts. were obsd. Deactivation of the initially excited state by ISC seems to dominate as supported by computations. For NTCDA we obsd. a gas phase lifetime of 16 ps upon excitation at 351 nm. [on SciFinder(R)] |
| 20. | Richter, Robert; Röhr, Merle I S; Zimmermann, Tobias; Petersen, Jens; Heidrich, Christoph; Rahner, Ramon; Moeller, Thomas; Dahl, Jeremy E; Carlson, Robert M K; Mitric, Roland; Rander, Torbjoern; Merli, Andrea. Laser-induced fluorescence of free diamondoid molecules. Journal Article Physical Chemistry Chemical Physics, 17 (6), pp. 4739–4749, 2015, ISSN: 1463-9076. @article{Richter2015a, title = {Laser-induced fluorescence of free diamondoid molecules.}, author = {Robert Richter and Merle I S Röhr and Tobias Zimmermann and Jens Petersen and Christoph Heidrich and Ramon Rahner and Thomas Moeller and Jeremy E Dahl and Robert M K Carlson and Roland Mitric and Torbjoern Rander and Andrea. Merli}, doi = {10.1039/C4CP04423A}, issn = {1463-9076}, year = {2015}, date = {2015-01-01}, journal = {Physical Chemistry Chemical Physics}, volume = {17}, number = {6}, pages = {4739--4749}, publisher = {Royal Society of Chemistry}, abstract = {We observe the fluorescence of pristine diamondoids in the gas phase, excited using narrow band UV laser light. The emission spectra show well-defined features, which can be attributed to transitions from the excited electronic state into different vibrational modes of the electronic ground state. We assign the normal modes responsible for the vibrational bands, and det. the geometry of the excited states. Calcns. indicate that for large diamondoids, the spectral bands do not result from progressions of single modes, but rather from combination bands composed of a large no. of $Delta$v = 1 transitions. The vibrational modes detg. the spectral envelope can mainly be assigned to wagging and twisting modes of the surface atoms. We conclude that our theor. approach accurately describes the photophysics in diamondoids and possibly other hydrocarbons in general. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } We observe the fluorescence of pristine diamondoids in the gas phase, excited using narrow band UV laser light. The emission spectra show well-defined features, which can be attributed to transitions from the excited electronic state into different vibrational modes of the electronic ground state. We assign the normal modes responsible for the vibrational bands, and det. the geometry of the excited states. Calcns. indicate that for large diamondoids, the spectral bands do not result from progressions of single modes, but rather from combination bands composed of a large no. of $Delta$v = 1 transitions. The vibrational modes detg. the spectral envelope can mainly be assigned to wagging and twisting modes of the surface atoms. We conclude that our theor. approach accurately describes the photophysics in diamondoids and possibly other hydrocarbons in general. [on SciFinder(R)] |
| 19. | Giegerich, Jens; Petersen, Jens; Mitric, Roland; Fischer, Ingo. Photodissociation dynamics of propargylene, HCCCH. Journal Article Physical Chemistry Chemical Physics, 16 (13), pp. 6294–6302, 2014, ISSN: 1463-9076. @article{Giegerich2014, title = {Photodissociation dynamics of propargylene, HCCCH.}, author = {Jens Giegerich and Jens Petersen and Roland Mitric and Ingo. Fischer}, doi = {10.1039/c3cp53213e}, issn = {1463-9076}, year = {2014}, date = {2014-01-01}, journal = {Physical Chemistry Chemical Physics}, volume = {16}, number = {13}, pages = {6294--6302}, publisher = {Royal Society of Chemistry}, abstract = {We report a joint theor. and exptl. study on the photodissocn. of the C3H2 isomer propargylene, HCCCH, combining velocity map imaging with nonadiabatic trajectory surface hopping calcns. Propargylene loses an H-atom, after laser excitation at around 250 nm, presumably to the T6 state. The photofragment angular distribution exhibits only a very small anisotropy, but the H-atom translational energy distribution extends to high energies and shows an expectation value of 〈fT〉, the fraction of excess energy released as translation, of 48%, outside the range expected for a statistical reaction mechanism. The computations suggest a predissocn. in the T4-T6 state and lead to a translational energy distribution and photofragment angular distribution that match the exptl. obsd. ones very well. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report a joint theor. and exptl. study on the photodissocn. of the C3H2 isomer propargylene, HCCCH, combining velocity map imaging with nonadiabatic trajectory surface hopping calcns. Propargylene loses an H-atom, after laser excitation at around 250 nm, presumably to the T6 state. The photofragment angular distribution exhibits only a very small anisotropy, but the H-atom translational energy distribution extends to high energies and shows an expectation value of 〈fT〉, the fraction of excess energy released as translation, of 48%, outside the range expected for a statistical reaction mechanism. The computations suggest a predissocn. in the T4-T6 state and lead to a translational energy distribution and photofragment angular distribution that match the exptl. obsd. ones very well. [on SciFinder(R)] |
| 18. | Richter, Robert; Wolter, David; Zimmermann, Tobias; Landt, Lasse; Knecht, Andre; Heidrich, Christoph; Merli, Andrea; Dopfer, Otto; Reiss, Philipp; Ehresmann, Arno; Petersen, Jens; Dahl, Jeremy E; Carlson, Robert M K; Bostedt, Christoph; Moeller, Thomas; Mitric, Roland; Rander, Torbjoern. Size and shape dependent photoluminescence and excited state decay rates of diamondoids. Journal Article Physical Chemistry Chemical Physics, 16 (7), pp. 3070–3076, 2014, ISSN: 1463-9076. @article{Richter2014, title = {Size and shape dependent photoluminescence and excited state decay rates of diamondoids.}, author = {Robert Richter and David Wolter and Tobias Zimmermann and Lasse Landt and Andre Knecht and Christoph Heidrich and Andrea Merli and Otto Dopfer and Philipp Reiss and Arno Ehresmann and Jens Petersen and Jeremy E Dahl and Robert M K Carlson and Christoph Bostedt and Thomas Moeller and Roland Mitric and Torbjoern. Rander}, doi = {10.1039/C3CP54570A}, issn = {1463-9076}, year = {2014}, date = {2014-01-01}, journal = {Physical Chemistry Chemical Physics}, volume = {16}, number = {7}, pages = {3070--3076}, publisher = {Royal Society of Chemistry}, abstract = {We present photoluminescence spectra and excited state decay rates of a series of diamondoids, which represent mol. structural analogs to H-passivated bulk diamond. Specific isomers of the 5 smallest diamondoids (adamantane-pentamantane) were brought into the gas phase and irradiated with synchrotron radiation. All investigated compds. show intrinsic photoluminescence in the UV spectral region. The emission spectra exhibit pronounced vibrational fine structure which is analyzed using quantum chem. calcns. We show that the geometrical relaxation of the 1st excited state of adamantane, exhibiting Rydberg character, leads to the loss of Td symmetry. The luminescence of adamantane is attributed to a transition from the delocalized 1st excited state into different vibrational modes of the electronic ground state. Similar geometrical changes of the excited state structure were also identified in the other investigated diamondoids. The excited state decay rates show a clear dependence on the size of the diamondoid, but are independent of the particle geometry, further indicating a loss of particle symmetry upon electronic excitation. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } We present photoluminescence spectra and excited state decay rates of a series of diamondoids, which represent mol. structural analogs to H-passivated bulk diamond. Specific isomers of the 5 smallest diamondoids (adamantane-pentamantane) were brought into the gas phase and irradiated with synchrotron radiation. All investigated compds. show intrinsic photoluminescence in the UV spectral region. The emission spectra exhibit pronounced vibrational fine structure which is analyzed using quantum chem. calcns. We show that the geometrical relaxation of the 1st excited state of adamantane, exhibiting Rydberg character, leads to the loss of Td symmetry. The luminescence of adamantane is attributed to a transition from the delocalized 1st excited state into different vibrational modes of the electronic ground state. Similar geometrical changes of the excited state structure were also identified in the other investigated diamondoids. The excited state decay rates show a clear dependence on the size of the diamondoid, but are independent of the particle geometry, further indicating a loss of particle symmetry upon electronic excitation. [on SciFinder(R)] |
| 17. | Gell, Lars; Kulesza, Alexander; Petersen, Jens; Röhr, Merle I S; Mitric, Roland; Bonacic-Koutecky, Vlasta. Tuning Structural and Optical Properties of Thiolate-Protected Silver Clusters by Formation of a Silver Core with Confined Electrons. Journal Article Journal of Physical Chemistry C, 117 (28), pp. 14824–14831, 2013, ISSN: 1932-7447. @article{Gell2013, title = {Tuning Structural and Optical Properties of Thiolate-Protected Silver Clusters by Formation of a Silver Core with Confined Electrons.}, author = {Lars Gell and Alexander Kulesza and Jens Petersen and Merle I S Röhr and Roland Mitric and Vlasta. Bonacic-Koutecky}, doi = {10.1021/jp402931w}, issn = {1932-7447}, year = {2013}, date = {2013-01-01}, journal = {Journal of Physical Chemistry C}, volume = {117}, number = {28}, pages = {14824--14831}, publisher = {American Chemical Society}, abstract = {The authors present a systematic theor. study of the structural and optical properties of thiolate-protected Ag clusters with the goal to design species exhibiting strong absorption and fluorescence in the UV-visible spectral range. The optical properties can be tuned by creating systems with different counts of confined electrons within the cluster core. Liganded Ag complexes with n Ag atoms (Agn) and x ligands (Lx) in anionic complexes [AgnLx]- with L = SMe are considered. Variation of the compn. ratio gives rise to systems with (i) zero confined electrons for x = n + 1, (ii) 2 confined electrons for x = n - 1, and (iii) 4 confined electrons for x = n - 3. The no. of confined electrons within the cluster core and the geometric structure of the latter are responsible for the spectral patterns, giving rise to intense absorption transitions and fluorescence in the visible or even IR range. The results open a perspective for the rational design of stable ligand-protected Ag cluster chromophores that might find numerous applications in the field of biosensing. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } The authors present a systematic theor. study of the structural and optical properties of thiolate-protected Ag clusters with the goal to design species exhibiting strong absorption and fluorescence in the UV-visible spectral range. The optical properties can be tuned by creating systems with different counts of confined electrons within the cluster core. Liganded Ag complexes with n Ag atoms (Agn) and x ligands (Lx) in anionic complexes [AgnLx]- with L = SMe are considered. Variation of the compn. ratio gives rise to systems with (i) zero confined electrons for x = n + 1, (ii) 2 confined electrons for x = n - 1, and (iii) 4 confined electrons for x = n - 3. The no. of confined electrons within the cluster core and the geometric structure of the latter are responsible for the spectral patterns, giving rise to intense absorption transitions and fluorescence in the visible or even IR range. The results open a perspective for the rational design of stable ligand-protected Ag cluster chromophores that might find numerous applications in the field of biosensing. [on SciFinder(R)] |
| 16. | Röhr, Merle I S; Petersen, Jens; Wohlgemuth, Matthias; Bonacic-Koutecky, Vlasta; Mitric, Roland. Nonlinear Absorption Dynamics Using Field-Induced Surface Hopping: Zinc Porphyrin in Water. Journal Article ChemPhysChem, 14 (7), pp. 1377–1386, 2013, ISSN: 1439-4235. @article{Röhr2013, title = {Nonlinear Absorption Dynamics Using Field-Induced Surface Hopping: Zinc Porphyrin in Water.}, author = {Merle I S Röhr and Jens Petersen and Matthias Wohlgemuth and Vlasta Bonacic-Koutecky and Roland. Mitric}, doi = {10.1002/cphc.201300053}, issn = {1439-4235}, year = {2013}, date = {2013-01-01}, journal = {ChemPhysChem}, volume = {14}, number = {7}, pages = {1377--1386}, publisher = {Wiley-VCH Verlag GmbH & Co. KGaA}, abstract = {The authors present the application of their field-induced surface-hopping (FISH) method to simulate nonlinear absorption dynamics induced by strong nonresonant laser fields. The authors provide a systematic comparison of the FISH approach with exact quantum dynamics simulations on a multi-state model system and demonstrate that FISH allows for accurate simulations of nonlinear excitation processes including multiphoton electronic transitions. In particular, two different approaches for simulating two-photon transitions are compared. The first approach is essentially exact and involves the soln. of the time-dependent Schrodinger equation in an extended manifold of excited states, while in the second one only transiently populated nonessential states are replaced by an effective quadratic coupling term, and dynamics is performed in a considerably smaller manifold of states. The authors illustrate the applicability of this method to complex mol. systems by simulating the linear and nonlinear laser-driven dynamics in zinc porphyrin in the gas phase and in water. For this purpose, the FISH approach is connected with the quantum mech.-mol. mech. approach (QM/MM) which is generally applicable to large classes of complex systems. The finding that multiphoton absorption and dynamics increase the population of higher excited states of Zn porphyrin in the nonlinear regime, in particular in soln., provides a means for manipulating excited-state properties, such as transient absorption dynamics and electronic relaxation. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } The authors present the application of their field-induced surface-hopping (FISH) method to simulate nonlinear absorption dynamics induced by strong nonresonant laser fields. The authors provide a systematic comparison of the FISH approach with exact quantum dynamics simulations on a multi-state model system and demonstrate that FISH allows for accurate simulations of nonlinear excitation processes including multiphoton electronic transitions. In particular, two different approaches for simulating two-photon transitions are compared. The first approach is essentially exact and involves the soln. of the time-dependent Schrodinger equation in an extended manifold of excited states, while in the second one only transiently populated nonessential states are replaced by an effective quadratic coupling term, and dynamics is performed in a considerably smaller manifold of states. The authors illustrate the applicability of this method to complex mol. systems by simulating the linear and nonlinear laser-driven dynamics in zinc porphyrin in the gas phase and in water. For this purpose, the FISH approach is connected with the quantum mech.-mol. mech. approach (QM/MM) which is generally applicable to large classes of complex systems. The finding that multiphoton absorption and dynamics increase the population of higher excited states of Zn porphyrin in the nonlinear regime, in particular in soln., provides a means for manipulating excited-state properties, such as transient absorption dynamics and electronic relaxation. [on SciFinder(R)] |
| 15. | Tomasello, Gaia; Wohlgemuth, Matthias; Petersen, Jens; Mitric, Roland. Photodynamics of Free and Solvated Tyrosine. Journal Article Journal of Physical Chemistry B, 116 (30), pp. 8762–8770, 2012, ISSN: 1520-5207. @article{Tomasello2012, title = {Photodynamics of Free and Solvated Tyrosine.}, author = {Gaia Tomasello and Matthias Wohlgemuth and Jens Petersen and Roland. Mitric}, doi = {10.1021/jp302179m}, issn = {1520-5207}, year = {2012}, date = {2012-01-01}, journal = {Journal of Physical Chemistry B}, volume = {116}, number = {30}, pages = {8762--8770}, publisher = {American Chemical Society}, abstract = {We present a theor. simulation, physicochem. of the ultrafast nonadiabatic photodynamics of tyrosine in the gas phase and in water. For this purpose, we combine our TDDFT/MM nonadiabatic dynamics (Wohlgemuth et al. J. Chem. Phys. 2011, 135, 054105) with the field-induced surface hopping method (Mitric, et al. Phys. Rev. A 2009, 79, 053416) allowing us to explicitly include the nonadiabatic effects as well as femtosecond laser radiation excitation into the simulation, physicochem. Our results reveal an ultrafast deactivation of the initially excited bright $pi$$pi$* state by internal conversion to a dark n$pi$* state. We observe deactivation channels along the O-H stretching coordinate as well as involving the N-H bond cleavage of the amino group followed by proton transfer to the phenol ring, which is in agreement with previous static energy path calcns. However, since in the gas phase the canonical form of tyrosine is the most stable one, the proton transfer proceeds in two steps, starting from the carboxyl group that first passes its proton to the amino group, from where it finally moves to the phenol ring. Furthermore, we also investigate the influence of water on the relaxation processes. For the system of tyrosine with three explicit water mols. solvating the amino group, embedded in a classical water sphere, we also observe a relaxation channel involving proton transfer to the phenol ring. However, in aq. environment, a water mol. near the protonated amino group of tyrosine acts as a mediator for the proton transfer, underlining the importance of the solvent in nonradiative relaxation processes of amino acids. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } We present a theor. simulation, physicochem. of the ultrafast nonadiabatic photodynamics of tyrosine in the gas phase and in water. For this purpose, we combine our TDDFT/MM nonadiabatic dynamics (Wohlgemuth et al. J. Chem. Phys. 2011, 135, 054105) with the field-induced surface hopping method (Mitric, et al. Phys. Rev. A 2009, 79, 053416) allowing us to explicitly include the nonadiabatic effects as well as femtosecond laser radiation excitation into the simulation, physicochem. Our results reveal an ultrafast deactivation of the initially excited bright $pi$$pi$* state by internal conversion to a dark n$pi$* state. We observe deactivation channels along the O-H stretching coordinate as well as involving the N-H bond cleavage of the amino group followed by proton transfer to the phenol ring, which is in agreement with previous static energy path calcns. However, since in the gas phase the canonical form of tyrosine is the most stable one, the proton transfer proceeds in two steps, starting from the carboxyl group that first passes its proton to the amino group, from where it finally moves to the phenol ring. Furthermore, we also investigate the influence of water on the relaxation processes. For the system of tyrosine with three explicit water mols. solvating the amino group, embedded in a classical water sphere, we also observe a relaxation channel involving proton transfer to the phenol ring. However, in aq. environment, a water mol. near the protonated amino group of tyrosine acts as a mediator for the proton transfer, underlining the importance of the solvent in nonradiative relaxation processes of amino acids. [on SciFinder(R)] |
| 14. | Petersen, Jens; Mitric, Roland. Electronic coherence within the semiclassical field-induced surface hopping method: strong field quantum control in K2. Journal Article Physical Chemistry Chemical Physics, 14 (23), pp. 8299–8306, 2012, ISSN: 1463-9076. @article{Petersen2012, title = {Electronic coherence within the semiclassical field-induced surface hopping method: strong field quantum control in K2.}, author = {Jens Petersen and Roland. Mitric}, doi = {10.1039/c2cp40747g}, issn = {1463-9076}, year = {2012}, date = {2012-01-01}, journal = {Physical Chemistry Chemical Physics}, volume = {14}, number = {23}, pages = {8299--8306}, publisher = {Royal Society of Chemistry}, abstract = {We demonstrate that the semiclassical field-induced surface hopping (FISH) method (Mitric et al., Phys. Rev. A: At., Mol., Opt. Phys., 2009, 79, 053416.) accurately describes the selective coherent control of electronic state populations. With the example of the strong field control in the potassium dimer using phase-coherent double pulse sequences, we present a detailed comparison between FISH simulations and exact quantum dynamics. We show that for short pulses the variation of the time delay between the subpulses allows for a selective population of the desired final state with high efficiency. Furthermore, also for pulses of longer time duration, when substantial nuclear motion takes place during the action of the pulse, optimized pulse shapes can be obtained which lead to selective population transfer. For both types of pulses, the FISH method almost perfectly reproduces the exact quantum mech. electronic population dynamics, fully taking account of the electronic coherence, and describes the leading features of the nuclear dynamics accurately. Due to the significantly higher computational efficiency of FISH as a trajectory-based method compared to full quantum dynamics simulations, this offers the possibility to theor. investigate control expts. on realistic systems including all nuclear degrees of freedom. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } We demonstrate that the semiclassical field-induced surface hopping (FISH) method (Mitric et al., Phys. Rev. A: At., Mol., Opt. Phys., 2009, 79, 053416.) accurately describes the selective coherent control of electronic state populations. With the example of the strong field control in the potassium dimer using phase-coherent double pulse sequences, we present a detailed comparison between FISH simulations and exact quantum dynamics. We show that for short pulses the variation of the time delay between the subpulses allows for a selective population of the desired final state with high efficiency. Furthermore, also for pulses of longer time duration, when substantial nuclear motion takes place during the action of the pulse, optimized pulse shapes can be obtained which lead to selective population transfer. For both types of pulses, the FISH method almost perfectly reproduces the exact quantum mech. electronic population dynamics, fully taking account of the electronic coherence, and describes the leading features of the nuclear dynamics accurately. Due to the significantly higher computational efficiency of FISH as a trajectory-based method compared to full quantum dynamics simulations, this offers the possibility to theor. investigate control expts. on realistic systems including all nuclear degrees of freedom. [on SciFinder(R)] |
| 13. | Röhr, M I S; Petersen, J; Brunet, C; Antoine, R; Broyer, M; Dugourd, P; Bonacic-Koutecky, V; OHair, R A J; Mitric, R Synthesis and Spectroscopic Characterization of Diphenylargentate, [(C6H5)2Ag]-. Journal Article Journal of Physical Chemistry Letters, 3 (9), pp. 1197–1201, 2012, ISSN: 1948-7185. @article{Röhr2012, title = {Synthesis and Spectroscopic Characterization of Diphenylargentate, [(C6H5)2Ag]-.}, author = {M I S Röhr and J Petersen and C Brunet and R Antoine and M Broyer and P Dugourd and V Bonacic-Koutecky and R A J OHair and R Mitric}, doi = {10.1021/jz300280f}, issn = {1948-7185}, year = {2012}, date = {2012-01-01}, journal = {Journal of Physical Chemistry Letters}, volume = {3}, number = {9}, pages = {1197--1201}, publisher = {American Chemical Society}, abstract = {The structural and optical properties are presented of the isolated Ph2Ag-, which was synthesized by multistage mass spectrometry in a quadrupole ion trap. The exptl. photodetachment spectrum was obtained by action spectroscopy. Comparison with quantum chem. calcns. of the electronic absorption spectrum allows for a precise characterization of the spectroscopic features, showing that in the low-energy regime, the optical properties of diphenylargentate bear a significant resemblance to those of at. Ag. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } The structural and optical properties are presented of the isolated Ph2Ag-, which was synthesized by multistage mass spectrometry in a quadrupole ion trap. The exptl. photodetachment spectrum was obtained by action spectroscopy. Comparison with quantum chem. calcns. of the electronic absorption spectrum allows for a precise characterization of the spectroscopic features, showing that in the low-energy regime, the optical properties of diphenylargentate bear a significant resemblance to those of at. Ag. [on SciFinder(R)] |
| 12. | Petersen, Jens; Wohlgemuth, Matthias; Sellner, Bernhard; Bonacic-Koutecky, Vlasta; Lischka, Hans; Mitric, Roland. Laser pulse trains for controlling excited state dynamics of adenine in water. Journal Article Physical Chemistry Chemical Physics, 14 (14), pp. 4687–4694, 2012, ISSN: 1463-9076. @article{Petersen2012a, title = {Laser pulse trains for controlling excited state dynamics of adenine in water.}, author = {Jens Petersen and Matthias Wohlgemuth and Bernhard Sellner and Vlasta Bonacic-Koutecky and Hans Lischka and Roland. Mitric}, doi = {10.1039/c2cp24002e}, issn = {1463-9076}, year = {2012}, date = {2012-01-01}, journal = {Physical Chemistry Chemical Physics}, volume = {14}, number = {14}, pages = {4687--4694}, publisher = {Royal Society of Chemistry}, abstract = {The authors investigate theor. the control of the ultrafast excited state dynamics of adenine in water by laser pulse trains, with the aim to extend the excited state lifetime and to suppress nonradiative relaxation processes. For this purpose, the authors introduce the combination of their field-induced surface hopping method (FISH) with the quantum mech.-mol. mech. (QM/MM) technique for simulating the laser-driven dynamics in the condensed phase under explicit inclusion of the solvent environment. Moreover, the authors employ parametric pulse shaping in the frequency domain to design simplified laser pulse trains allowing to establish a direct link between the pulse parameters and the controlled dynamics. The authors construct pulse trains which achieve a high excitation efficiency and at the same time keep a high excited state population for a significantly extended time period compared to the uncontrolled dynamics. The control mechanism involves a sequential cycling of the population between the lowest and higher excited states, thereby utilizing the properties of the corresponding potential energy surfaces to avoid conical intersections and thus to suppress the nonradiative decay to the ground state. The authors' findings provide a means to increase the fluorescence yield of mols. with an intrinsically very short excited state lifetime, which can lead to novel applications of shaped laser fields in the context of biosensing. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } The authors investigate theor. the control of the ultrafast excited state dynamics of adenine in water by laser pulse trains, with the aim to extend the excited state lifetime and to suppress nonradiative relaxation processes. For this purpose, the authors introduce the combination of their field-induced surface hopping method (FISH) with the quantum mech.-mol. mech. (QM/MM) technique for simulating the laser-driven dynamics in the condensed phase under explicit inclusion of the solvent environment. Moreover, the authors employ parametric pulse shaping in the frequency domain to design simplified laser pulse trains allowing to establish a direct link between the pulse parameters and the controlled dynamics. The authors construct pulse trains which achieve a high excitation efficiency and at the same time keep a high excited state population for a significantly extended time period compared to the uncontrolled dynamics. The control mechanism involves a sequential cycling of the population between the lowest and higher excited states, thereby utilizing the properties of the corresponding potential energy surfaces to avoid conical intersections and thus to suppress the nonradiative decay to the ground state. The authors' findings provide a means to increase the fluorescence yield of mols. with an intrinsically very short excited state lifetime, which can lead to novel applications of shaped laser fields in the context of biosensing. [on SciFinder(R)] |
| 11. | Stanzel, Joerg; Neeb, Matthias; Eberhardt, Wolfgang; Lisinetskaya, Polina G; Petersen, Jens; Mitric, Roland. Switching from molecular to bulk-like dynamics in electronic relaxation of a small gold cluster. Journal Article Physical Review A: Atomic, Molecular, and Optical Physics, 85 (1-A), pp. 013201/1–013201/6, 2012, ISSN: 1050-2947. @article{Stanzel2012, title = {Switching from molecular to bulk-like dynamics in electronic relaxation of a small gold cluster.}, author = {Joerg Stanzel and Matthias Neeb and Wolfgang Eberhardt and Polina G Lisinetskaya and Jens Petersen and Roland. Mitric}, doi = {10.1103/PhysRevA.85.013201}, issn = {1050-2947}, year = {2012}, date = {2012-01-01}, journal = {Physical Review A: Atomic, Molecular, and Optical Physics}, volume = {85}, number = {1-A}, pages = {013201/1--013201/6}, publisher = {American Physical Society}, abstract = {We have investigated the ultrafast electronic relaxation of Au7- using time-resolved photoelectron spectroscopy combined with first-principles simulations of the excited-state dynamics. Unlike previous findings, which have demonstrated molecularlike excited-state relaxation in Au7- at low excitation energy (1.56 eV), we show here that excitation with 3.12 eV leads to bulklike electronic relaxation without a considerable change of geometry. The exptl. findings are fully supported by theor. simulations, which reveal a bulklike electron-hole relaxation mechanism in a far band-gap cluster. Our findings demonstrate that small gold clusters in the sub-nm size range can exhibit either molecularlike or bulklike properties, depending on the excitation energy. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } We have investigated the ultrafast electronic relaxation of Au7- using time-resolved photoelectron spectroscopy combined with first-principles simulations of the excited-state dynamics. Unlike previous findings, which have demonstrated molecularlike excited-state relaxation in Au7- at low excitation energy (1.56 eV), we show here that excitation with 3.12 eV leads to bulklike electronic relaxation without a considerable change of geometry. The exptl. findings are fully supported by theor. simulations, which reveal a bulklike electron-hole relaxation mechanism in a far band-gap cluster. Our findings demonstrate that small gold clusters in the sub-nm size range can exhibit either molecularlike or bulklike properties, depending on the excitation energy. [on SciFinder(R)] |
| 10. | Mitric, Roland; Petersen, Jens; Bonacic-Koutecky, Vlasta. Multistate nonadiabatic dynamics Journal Article Advanced Series in Physical Chemistry, 17 (Conical Intersections), pp. 497–568, 2011, ISSN: 0219-1784. @article{Mitric2011, title = {Multistate nonadiabatic dynamics}, author = {Roland Mitric and Jens Petersen and Vlasta. Bonacic-Koutecky}, issn = {0219-1784}, year = {2011}, date = {2011-01-01}, journal = {Advanced Series in Physical Chemistry}, volume = {17}, number = {Conical Intersections}, pages = {497--568}, publisher = {World Scientific Publishing Co. Pte. Ltd.}, abstract = {A review presents the development of theor. methods for the simulation of nonadiabatic dynamics and its manipulation by laser fields in complex systems accounting for all degrees of freedom. It describes nonadiabatic dynamics 'on the fly' in the frame of time-dependent d. functional theory and its approx. tight-binding version. It outlines the procedure for the simulation of time-resolved photoelectron spectra based on the nonadiabatic dynamics 'on the fly' and the field-induced surface hopping method which is based on the combination of quantum electronic state population dynamics with classical nuclear dynamics. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } A review presents the development of theor. methods for the simulation of nonadiabatic dynamics and its manipulation by laser fields in complex systems accounting for all degrees of freedom. It describes nonadiabatic dynamics 'on the fly' in the frame of time-dependent d. functional theory and its approx. tight-binding version. It outlines the procedure for the simulation of time-resolved photoelectron spectra based on the nonadiabatic dynamics 'on the fly' and the field-induced surface hopping method which is based on the combination of quantum electronic state population dynamics with classical nuclear dynamics. [on SciFinder(R)] |
| 9. | Mitric, Roland; Petersen, Jens; Wohlgemuth, Matthias; Werner, Ute; Bonacic-Koutecky, Vlasta. Field-induced surface hopping method for probing transition state nonadiabatic dynamics of Ag3. Journal Article Physical Chemistry Chemical Physics, 13 (19), pp. 8690–8696, 2011, ISSN: 1463-9076. @article{Mitric2011a, title = {Field-induced surface hopping method for probing transition state nonadiabatic dynamics of Ag3.}, author = {Roland Mitric and Jens Petersen and Matthias Wohlgemuth and Ute Werner and Vlasta. Bonacic-Koutecky}, doi = {10.1039/c0cp02935a}, issn = {1463-9076}, year = {2011}, date = {2011-01-01}, journal = {Physical Chemistry Chemical Physics}, volume = {13}, number = {19}, pages = {8690--8696}, publisher = {Royal Society of Chemistry}, abstract = {We present the simulation of time-resolved photoelectron spectra of Ag3 involving excitation from the linear transition state, where nonadiabatic relaxation takes place in a complex manifold of electronic states. Thus, we address ultrafast processes reachable by neg. ion-to neutral-to pos. ion (NeNePo) spectroscopy starting from the linear Ag3- anionic species. For this purpose we use our newly developed field-induced surface hopping method (FISH) augmented for the description of photoionization processes. Furthermore we employ our method for nonadiabatic mol. dynamics "on the fly" in the framework of time-dependent d. functional theory generalized for open shell systems. Our presented approach is generally applicable for the prediction of time-resolved photoelectron spectra and their anal. in systems with complex electronic structure as well as many nuclear degrees freedom. This theor. development should serve to stimulate new ultrafast expts. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } We present the simulation of time-resolved photoelectron spectra of Ag3 involving excitation from the linear transition state, where nonadiabatic relaxation takes place in a complex manifold of electronic states. Thus, we address ultrafast processes reachable by neg. ion-to neutral-to pos. ion (NeNePo) spectroscopy starting from the linear Ag3- anionic species. For this purpose we use our newly developed field-induced surface hopping method (FISH) augmented for the description of photoionization processes. Furthermore we employ our method for nonadiabatic mol. dynamics "on the fly" in the framework of time-dependent d. functional theory generalized for open shell systems. Our presented approach is generally applicable for the prediction of time-resolved photoelectron spectra and their anal. in systems with complex electronic structure as well as many nuclear degrees freedom. This theor. development should serve to stimulate new ultrafast expts. [on SciFinder(R)] |
| 8. | Mitric, R; Petersen, J; Kulesza, A; Röhr, M I S; Bonacic-Koutecky, V; Brunet, C; Antoine, R; Dugourd, P; Broyer, M; O'Hair, R A J Gas-phase synthesis and vibronic action spectroscopy of Ag2H+. Journal Article Journal of Physical Chemistry Letters, 2 (6), pp. 548–552, 2011, ISSN: 1948-7185. @article{Mitric2011b, title = {Gas-phase synthesis and vibronic action spectroscopy of Ag2H+.}, author = {R Mitric and J Petersen and A Kulesza and M I S Röhr and V Bonacic-Koutecky and C Brunet and R Antoine and P Dugourd and M Broyer and R A J O'Hair}, doi = {10.1021/jz101733v}, issn = {1948-7185}, year = {2011}, date = {2011-01-01}, journal = {Journal of Physical Chemistry Letters}, volume = {2}, number = {6}, pages = {548--552}, publisher = {American Chemical Society}, abstract = {The authors present the first vibrationally resolved electronic spectrum for the isolated silver hydride cation Ag2H+, which has been synthesized by multistage mass spectrometry in a quadrupole ion trap. The exptl. photofragmentation spectrum has been obtained by action spectroscopy. High-level ab initio simulations reproduce exptl. findings and provide precise assignment of structural properties of ground and excited electronic states of Ag2H+, which serves as an intermediate in important chem. reactions such as carbon-carbon coupling. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } The authors present the first vibrationally resolved electronic spectrum for the isolated silver hydride cation Ag2H+, which has been synthesized by multistage mass spectrometry in a quadrupole ion trap. The exptl. photofragmentation spectrum has been obtained by action spectroscopy. High-level ab initio simulations reproduce exptl. findings and provide precise assignment of structural properties of ground and excited electronic states of Ag2H+, which serves as an intermediate in important chem. reactions such as carbon-carbon coupling. [on SciFinder(R)] |
| 7. | Mitric, Roland; Petersen, Jens; Wohlgemuth, Matthias; Werner, Ute; Bonacic-Koutecky, Vlasta; Woeste, Ludger; Jortner, Joshua. Time-Resolved Femtosecond Photoelectron Spectroscopy by Field-Induced Surface Hopping. Journal Article Journal of Physical Chemistry A, 115 (16), pp. 3755–3765, 2011, ISSN: 1089-5639. @article{Mitric2011c, title = {Time-Resolved Femtosecond Photoelectron Spectroscopy by Field-Induced Surface Hopping.}, author = {Roland Mitric and Jens Petersen and Matthias Wohlgemuth and Ute Werner and Vlasta Bonacic-Koutecky and Ludger Woeste and Joshua. Jortner}, doi = {10.1021/jp106355n}, issn = {1089-5639}, year = {2011}, date = {2011-01-01}, journal = {Journal of Physical Chemistry A}, volume = {115}, number = {16}, pages = {3755--3765}, publisher = {American Chemical Society}, abstract = {The authors present the extension of field-induced surface hopping method for the description of the photoionization process and the simulation of time-resolved photoelectron spectra (TRPES). This is based on the combination of nonadiabatic mol. dynamics on the fly in the framework of TDDFT generalized for open shell systems under the influence of laser fields with the approx. quantum mech. description of the photoionization process. Since arbitrary pulse shapes can be employed, this method can be also combined with the optimal control theory to steer the photoionization or to shape the outgoing electronic wavepackets. The authors illustrate method for the simulation of TRPES on the prototype system of Ag3, which involves excitation from the equil. triangular geometry, as well as excitation from the linear transition state, where in both cases nonadiabatic relaxation takes place in a complex manifold of electronic states. Approach represents a generally applicable method for the prediction of time-resolved photoelectron spectra and their anal. in systems with complex electronic structure as well as many nuclear degrees freedom. This theor. development should serve to stimulate new ultrafast expts. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } The authors present the extension of field-induced surface hopping method for the description of the photoionization process and the simulation of time-resolved photoelectron spectra (TRPES). This is based on the combination of nonadiabatic mol. dynamics on the fly in the framework of TDDFT generalized for open shell systems under the influence of laser fields with the approx. quantum mech. description of the photoionization process. Since arbitrary pulse shapes can be employed, this method can be also combined with the optimal control theory to steer the photoionization or to shape the outgoing electronic wavepackets. The authors illustrate method for the simulation of TRPES on the prototype system of Ag3, which involves excitation from the equil. triangular geometry, as well as excitation from the linear transition state, where in both cases nonadiabatic relaxation takes place in a complex manifold of electronic states. Approach represents a generally applicable method for the prediction of time-resolved photoelectron spectra and their anal. in systems with complex electronic structure as well as many nuclear degrees freedom. This theor. development should serve to stimulate new ultrafast expts. [on SciFinder(R)] |
| 6. | Petersen, Jens; Mitric, Roland; Bonacic-Koutecky, Vlasta; Wolf, Jean-Pierre; Roslund, Jonathan; Rabitz, Herschel. How shaped light discriminates nearly identical biochromophores. Journal Article Physical Review Letters, 105 (7), pp. 073003/1–073003/4, 2010, ISSN: 0031-9007. @article{Petersen2010, title = {How shaped light discriminates nearly identical biochromophores.}, author = {Jens Petersen and Roland Mitric and Vlasta Bonacic-Koutecky and Jean-Pierre Wolf and Jonathan Roslund and Herschel. Rabitz}, doi = {10.1103/PhysRevLett.105.073003}, issn = {0031-9007}, year = {2010}, date = {2010-01-01}, journal = {Physical Review Letters}, volume = {105}, number = {7}, pages = {073003/1--073003/4}, publisher = {American Physical Society}, abstract = {A review. We present a general mechanism for successful discrimination of spectroscopically indistinguishable biochromophores by shaped light. For this purpose we use nonadiabatic dynamics in excited electronic states in the frame of the field-induced surface hopping method driven by the exptl. shaped laser fields. Our findings show that optimal laser fields drive low-frequency vibrational modes localized in the side chains of two biochromophores, thus selecting the parts of their potential energy surfaces characterized by different transition dipole moments leading to different ionization probabilities. The presented mechanism leads to selective fluorescence depletion which serves as a discrimination signal. Our findings offer a promising perspective for using optimally shaped laser pulses in bioanal. applications by increasing the selectivity beyond the current capability. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } A review. We present a general mechanism for successful discrimination of spectroscopically indistinguishable biochromophores by shaped light. For this purpose we use nonadiabatic dynamics in excited electronic states in the frame of the field-induced surface hopping method driven by the exptl. shaped laser fields. Our findings show that optimal laser fields drive low-frequency vibrational modes localized in the side chains of two biochromophores, thus selecting the parts of their potential energy surfaces characterized by different transition dipole moments leading to different ionization probabilities. The presented mechanism leads to selective fluorescence depletion which serves as a discrimination signal. Our findings offer a promising perspective for using optimally shaped laser pulses in bioanal. applications by increasing the selectivity beyond the current capability. [on SciFinder(R)] |
| 5. | Mitric, Roland; Petersen, Jens; Bonacic-Koutecky, Vlasta. Laser-field-induced surface-hopping method for the simulation and control of ultrafast photodynamics. Journal Article Physical Review A: Atomic, Molecular, and Optical Physics, 79 (5, Pt. A), pp. 053416/1–053416/6, 2009, ISSN: 1050-2947. @article{Mitric2009a, title = {Laser-field-induced surface-hopping method for the simulation and control of ultrafast photodynamics.}, author = {Roland Mitric and Jens Petersen and Vlasta. Bonacic-Koutecky}, doi = {10.1103/PhysRevA.79.053416}, issn = {1050-2947}, year = {2009}, date = {2009-01-01}, journal = {Physical Review A: Atomic, Molecular, and Optical Physics}, volume = {79}, number = {5, Pt. A}, pages = {053416/1--053416/6}, publisher = {American Physical Society}, abstract = {The authors present the semiclassical laser-field-induced surface-hopping method for the simulation and control of coupled electron-nuclear dynamics in complex mol. systems including all degrees of freedom. The authors approach is based on the Wigner representation of quantum mechanics. The combination of the mol. dynamics "on the fly" employing quantum initial conditions with the surface-hopping procedure allows for the treatment of the electronic transitions induced by the laser field. The authors semiclassical approach reproduced accurately exact quantum dynamics in a two-electronic-state model system. The authors demonstrate the scope of their method on the example of the optimal pump-dump control of the trans-cis isomerization of a prototypical Schiff base mol. switch. The authors results show that selective photochem. can be achieved by shaped laser pulses which open new dynamical pathways by suppressing the isomerization through the conical intersections between electronic states. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } The authors present the semiclassical laser-field-induced surface-hopping method for the simulation and control of coupled electron-nuclear dynamics in complex mol. systems including all degrees of freedom. The authors approach is based on the Wigner representation of quantum mechanics. The combination of the mol. dynamics "on the fly" employing quantum initial conditions with the surface-hopping procedure allows for the treatment of the electronic transitions induced by the laser field. The authors semiclassical approach reproduced accurately exact quantum dynamics in a two-electronic-state model system. The authors demonstrate the scope of their method on the example of the optimal pump-dump control of the trans-cis isomerization of a prototypical Schiff base mol. switch. The authors results show that selective photochem. can be achieved by shaped laser pulses which open new dynamical pathways by suppressing the isomerization through the conical intersections between electronic states. [on SciFinder(R)] |
| 4. | Mitric, Roland; Petersen, Jens; Kulesza, Alexander; Bonacic-Koutecky, Vlasta; Tabarin, Thibault; Compagnon, Isabelle; Antoine, Rodolphe; Broyer, Michel; Dugourd, Philippe. Chemical Physics, 343 (2-3), pp. 372–380, 2008, ISSN: 0301-0104. @article{Mitric2008a, title = {Absorption properties of cationic silver cluster-tryptophan complexes: A model for photoabsorption and photoemission enhancement in nanoparticle-biomolecule systems.}, author = {Roland Mitric and Jens Petersen and Alexander Kulesza and Vlasta Bonacic-Koutecky and Thibault Tabarin and Isabelle Compagnon and Rodolphe Antoine and Michel Broyer and Philippe. Dugourd}, doi = {10.1016/j.chemphys.2007.09.033}, issn = {0301-0104}, year = {2008}, date = {2008-01-01}, journal = {Chemical Physics}, volume = {343}, number = {2-3}, pages = {372--380}, publisher = {Elsevier B.V.}, abstract = {The authors present a joint theor. and exptl. study of the size and structure selective absorption properties of cationic silver cluster-tryptophan (Trp-Ag+n}, keywords = {}, pubstate = {published}, tppubtype = {article} } The authors present a joint theor. and exptl. study of the size and structure selective absorption properties of cationic silver cluster-tryptophan (Trp-Ag+n |
| 3. | Tabarin, T; Antoine, R; Compagnon, I; Broyer, M; Dugourd, P; Mitric, R; Petersen, J; Bonacic-Koutecky, V Optical absorption of isolated silver cluster-tryptophan: A joint experimental and theoretical study. Journal Article European Physical Journal D: Atomic, Molecular, Optical and Plasma Physics, 43 (1-3), pp. 275–278, 2007, ISSN: 1434-6060. @article{Tabarin2007, title = {Optical absorption of isolated silver cluster-tryptophan: A joint experimental and theoretical study.}, author = {T Tabarin and R Antoine and I Compagnon and M Broyer and P Dugourd and R Mitric and J Petersen and V Bonacic-Koutecky}, doi = {10.1140/epjd/e2007-00118-5}, issn = {1434-6060}, year = {2007}, date = {2007-01-01}, journal = {European Physical Journal D: Atomic, Molecular, Optical and Plasma Physics}, volume = {43}, number = {1-3}, pages = {275--278}, publisher = {EDP Sciences}, abstract = {The authors present a joint exptl. and theor. gas phase study of photoabsorption and photofragmentation of Ag cluster-biomol. complexes. The authors demonstrate on the example of [Trp.Ag3]+ that binding of the metal cluster to a biomol. leads to a significant enhancement of the photoabsorption in comparison with [Trp.H]+ and [Trp.Ag]+. This enhancement arises due to the coupling between the excitations in the metallic subunit with charge transfer excitations between Ag cluster and tryptophan. The authors' exptl. studies show that Ag clusters up to eleven atoms can be bound to tryptophan and the authors present 1st results on the photofragmentation of the Trp.Ag+11 complex cation, in which properties of cluster subunit remain preserved. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } The authors present a joint exptl. and theor. gas phase study of photoabsorption and photofragmentation of Ag cluster-biomol. complexes. The authors demonstrate on the example of [Trp.Ag3]+ that binding of the metal cluster to a biomol. leads to a significant enhancement of the photoabsorption in comparison with [Trp.H]+ and [Trp.Ag]+. This enhancement arises due to the coupling between the excitations in the metallic subunit with charge transfer excitations between Ag cluster and tryptophan. The authors' exptl. studies show that Ag clusters up to eleven atoms can be bound to tryptophan and the authors present 1st results on the photofragmentation of the Trp.Ag+11 complex cation, in which properties of cluster subunit remain preserved. [on SciFinder(R)] |
| 2. | Mitric, Roland; Petersen, Jens; Kulesza, Alexander; Bonacic-Koutecky, Vlasta; Tabarin, Thibault; Compagnon, Isabelle; Antoine, Rodolphe; Broyer, Michel; Dugourd, Philippe. Photoabsorption and photofragmentation of isolated cationic silver cluster-tryptophan hybrid systems. Journal Article Journal of Chemical Physics, 127 (13), pp. 134301/1–134301/9, 2007, ISSN: 0021-9606. @article{Mitric2007a, title = {Photoabsorption and photofragmentation of isolated cationic silver cluster-tryptophan hybrid systems.}, author = {Roland Mitric and Jens Petersen and Alexander Kulesza and Vlasta Bonacic-Koutecky and Thibault Tabarin and Isabelle Compagnon and Rodolphe Antoine and Michel Broyer and Philippe. Dugourd}, doi = {10.1063/1.2772630}, issn = {0021-9606}, year = {2007}, date = {2007-01-01}, journal = {Journal of Chemical Physics}, volume = {127}, number = {13}, pages = {134301/1--134301/9}, publisher = {American Institute of Physics}, abstract = {The authors present a theor. study of the size and structure selective absorption properties of cationic silver cluster-tryptophan Trp-Ag+n (n = 2-5,9) hybrid systems supported by photofragmentation expts. The authors time-dependent d. functional theory calcns. provide insight into the nature of excitations in interacting nanoparticle-biomol. subunits and allow to det. characteristic spectral features as fingerprints of two different classes of structures: charge solvated and zwitterionic. Moreover, different types of charge transfer transitions have been identified. Charge transfer from $pi$ system of tryptophan to silver cluster occurs for charge solvated structures while charge transfer from silver to the NH+3 group takes place for zwitterionic structures. This has been confirmed by exptl. measured photofragmentation channels and mol. dynamics simulations. The authors findings provide fundamental insight into the structure- and size-dependent mechanism responsible for the enhanced absorption and emission in nanoparticle-biomol. hybrid systems. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } The authors present a theor. study of the size and structure selective absorption properties of cationic silver cluster-tryptophan Trp-Ag+n (n = 2-5,9) hybrid systems supported by photofragmentation expts. The authors time-dependent d. functional theory calcns. provide insight into the nature of excitations in interacting nanoparticle-biomol. subunits and allow to det. characteristic spectral features as fingerprints of two different classes of structures: charge solvated and zwitterionic. Moreover, different types of charge transfer transitions have been identified. Charge transfer from $pi$ system of tryptophan to silver cluster occurs for charge solvated structures while charge transfer from silver to the NH+3 group takes place for zwitterionic structures. This has been confirmed by exptl. measured photofragmentation channels and mol. dynamics simulations. The authors findings provide fundamental insight into the structure- and size-dependent mechanism responsible for the enhanced absorption and emission in nanoparticle-biomol. hybrid systems. [on SciFinder(R)] |
| 1. | Compagnon, Isabelle; Tabarin, Thibault; Antoine, Rodolphe; Broyer, Michel; Dugourd, Philippe; Mitric, Roland; Petersen, Jens; Bonacic-Koutecky, Vlasta. Journal of Chemical Physics, 125 (16), pp. 164326/1–164326/5, 2006, ISSN: 0021-9606. @article{Compagnon2006, title = {Spectroscopy of isolated, mass-selected tryptophan-Ag3 complexes: A model for photoabsorption enhancement in nanoparticle-biomolecule hybrid systems.}, author = {Isabelle Compagnon and Thibault Tabarin and Rodolphe Antoine and Michel Broyer and Philippe Dugourd and Roland Mitric and Jens Petersen and Vlasta. Bonacic-Koutecky}, doi = {10.1063/1.2357947}, issn = {0021-9606}, year = {2006}, date = {2006-01-01}, journal = {Journal of Chemical Physics}, volume = {125}, number = {16}, pages = {164326/1--164326/5}, publisher = {American Institute of Physics}, abstract = {Gas-phase studies of small metal cluster-biomol. complexes provide fundamental insights into the mechanism leading to enhanced optical absorption in nanoparticle-biomol. hybrid systems. Here the authors present, for the 1st time, a joint exptl. and theor. study of photoabsorption and photofragmentation of the Ag trimer-tryptophan cation complex ([TrptextperiodcenteredAg3]+). Binding the metal cluster to a biomol. leads to a remarkably high optical absorption as compared to the bare tryptophan or the [TrptextperiodcenteredAg]+ complex. As calcns. show this arises due to coupling between the excitations in the metallic subunit with a charge transfer excitation to the tryptophan mol. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } Gas-phase studies of small metal cluster-biomol. complexes provide fundamental insights into the mechanism leading to enhanced optical absorption in nanoparticle-biomol. hybrid systems. Here the authors present, for the 1st time, a joint exptl. and theor. study of photoabsorption and photofragmentation of the Ag trimer-tryptophan cation complex ([TrptextperiodcenteredAg3]+). Binding the metal cluster to a biomol. leads to a remarkably high optical absorption as compared to the bare tryptophan or the [TrptextperiodcenteredAg]+ complex. As calcns. show this arises due to coupling between the excitations in the metallic subunit with a charge transfer excitation to the tryptophan mol. [on SciFinder(R)] |