Matthias Wohlgemuth
PhD Student
Room: 02.006
Phone: +49-(0)931-31-88862
Mail: matthias.wohlgemuth@uni-wuerzburg.de
Scientific Vita
Dipl-Chem., Humboldt-Universität zu Berlin (2010) |
Research Interests
- Development of methods for the simulation and control of the ultrafast nonadiabatic dynamics in complex biomolecules, nanostructures and solvated molecular systems.
Publication List
15. | Miyazaki, M; Kamya, T; Wohlgemuth, M; Chatterjee, K; Mitric, R; Dopfer, O; Fujii, M Phys. Chem. Chem. Phys., 24 , pp. 73-85, 2021. @article{wohlgemuth2021, title = {Real-time observation of photoionization-induced water migration dynamics in 4-methylformanilide–water by picosecond time-resolved infrared spectroscopy and ab initio molecular dynamics simulations}, author = {M Miyazaki and T Kamya and M Wohlgemuth and K Chatterjee and R Mitric and O Dopfer and M Fujii}, url = {https://pubs.rsc.org/en/content/articlelanding/2022/CP/D1CP03327A}, doi = {https://doi.org/10.1039/D1CP03327A}, year = {2021}, date = {2021-10-01}, journal = {Phys. Chem. Chem. Phys.}, volume = {24}, pages = {73-85}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
14. | Wohlgemuth, Matthias; Mitric, Roland Excitation energy transport in DNA modelled by multi-chromophoric field-induced surface hopping Journal Article Phys. Chem. Chem. Phys. , 22 , pp. 16536-16551 , 2020. @article{wohlgemu_2020_jun, title = {Excitation energy transport in DNA modelled by multi-chromophoric field-induced surface hopping}, author = {Matthias Wohlgemuth and Roland Mitric}, url = {https://pubs.rsc.org/en/content/articlelanding/2020/cp/d0cp02255a#!divAbstract}, doi = {10.1039/D0CP02255A}, year = {2020}, date = {2020-06-03}, journal = {Phys. Chem. Chem. Phys. }, volume = {22}, pages = {16536-16551 }, abstract = {Absorption of ultraviolet light is known as a major source of carcinogenic mutations of DNA. The underlying processes of excitation energy dissipation are yet not fully understood. In this work we provide a new and generally applicable route for studying the excitation energy transport in multi-chromophoric complexes at an atomistic level. The surface-hopping approach in the frame of the extended Frenkel exciton model combined with QM/MM techniques allowed us to simulate the photodynamics of the alternating (dAdT)_{10}:(dAdT)_{10} double-stranded DNA. In accordance with recent experiments, we find that the excited state decay is multiexponential, involving a long and a short component which are due to two distinct mechanisms: formation of long-lived delocalized excitonic and charge transfer states vs. ultrafast decaying localized states resembling those of the bare nucleobases. Our simulations explain all stages of the ultrafast photodynamics including initial photoexcitation, dynamical evolution out of the Franck–Condon region, excimer formation and nonradiative relaxation to the ground state.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Absorption of ultraviolet light is known as a major source of carcinogenic mutations of DNA. The underlying processes of excitation energy dissipation are yet not fully understood. In this work we provide a new and generally applicable route for studying the excitation energy transport in multi-chromophoric complexes at an atomistic level. The surface-hopping approach in the frame of the extended Frenkel exciton model combined with QM/MM techniques allowed us to simulate the photodynamics of the alternating (dAdT)10:(dAdT)10 double-stranded DNA. In accordance with recent experiments, we find that the excited state decay is multiexponential, involving a long and a short component which are due to two distinct mechanisms: formation of long-lived delocalized excitonic and charge transfer states vs. ultrafast decaying localized states resembling those of the bare nucleobases. Our simulations explain all stages of the ultrafast photodynamics including initial photoexcitation, dynamical evolution out of the Franck–Condon region, excimer formation and nonradiative relaxation to the ground state. |
13. | Wohlgemuth, M; Miyazaki, M; Tsukuda, K; Weiler, M; Dopfer, O; Fujii, M; Mitric, R Deciphering environment effects in peptide bond solvation dynamics by experiment and theory Journal Article Phys. Chem. Chem. Phys., 19 , pp. 22564, 2017. @article{wohlgemuth2017, title = {Deciphering environment effects in peptide bond solvation dynamics by experiment and theory}, author = {M Wohlgemuth and M Miyazaki and K Tsukuda and M Weiler and O Dopfer and M Fujii and R Mitric}, url = {http://dx.doi.org/10.1039/C7CP03992A}, doi = {10.1039/C7CP03992A}, year = {2017}, date = {2017-08-04}, journal = {Phys. Chem. Chem. Phys.}, volume = {19}, pages = {22564}, abstract = {Most proteins work in aqueous solution and the interaction with water strongly affects their structure and function. However, experimentally the motion of a specific single water molecule is difficult to trace by conventional methods, because they average over the heterogeneous solvation structure of bulk water surrounding the protein. Here, we provide a detailed atomistic picture of the water rearrangement dynamics around the –CONH– peptide linkage in the two model systems formanilide and acetanilide, which simply differ by the presence of a methyl group at the peptide linkage. The combination of picosecond pump–probe time-resolved infrared spectroscopy and molecular dynamics simulations demonstrates that the solvation dynamics at the molecular level is strongly influenced by this small structural difference. The effective timescales for solvent migration triggered by ionization are mainly controlled by the efficiency of the kinetic energy redistribution rather than the shape of the potential energy surface. This approach provides a fundamental understanding of protein hydration and may help to design functional molecules in solution with tailored properties.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Most proteins work in aqueous solution and the interaction with water strongly affects their structure and function. However, experimentally the motion of a specific single water molecule is difficult to trace by conventional methods, because they average over the heterogeneous solvation structure of bulk water surrounding the protein. Here, we provide a detailed atomistic picture of the water rearrangement dynamics around the –CONH– peptide linkage in the two model systems formanilide and acetanilide, which simply differ by the presence of a methyl group at the peptide linkage. The combination of picosecond pump–probe time-resolved infrared spectroscopy and molecular dynamics simulations demonstrates that the solvation dynamics at the molecular level is strongly influenced by this small structural difference. The effective timescales for solvent migration triggered by ionization are mainly controlled by the efficiency of the kinetic energy redistribution rather than the shape of the potential energy surface. This approach provides a fundamental understanding of protein hydration and may help to design functional molecules in solution with tailored properties. |
12. | 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)] |
11. | Wohlgemuth, Matthias; Mitric, Roland. Photochemical Chiral Symmetry Breaking in Alanine. Journal Article Journal of Physical Chemistry A, 120 (45), pp. 8976–8982, 2016, ISSN: 1089-5639. @article{Wohlgemuth2016, title = {Photochemical Chiral Symmetry Breaking in Alanine.}, author = {Matthias Wohlgemuth and Roland. Mitric}, doi = {10.1021/acs.jpca.6b07611}, issn = {1089-5639}, year = {2016}, date = {2016-01-01}, journal = {Journal of Physical Chemistry A}, volume = {120}, number = {45}, pages = {8976--8982}, publisher = {American Chemical Society}, abstract = {We introduce a general theor. approach for the simulation of photochem. dynamics under the influence of circularly polarized light to explore the possibility of generating enantiomeric enrichment through polarized-light-selective photochem. The method is applied to the simulation of the photolysis of alanine, a prototype chiral amino acid. It is shown that a systematic enantiomeric enrichment can be obtained depending on the helicity of the circularly polarized light that induces the excited-state photochem. of alanine. By analyzing the patterns of the photoinduced fragmentation of alanine we find an inducible enantiomeric enrichment up to 1.7%, which is also in good correspondence to the exptl. findings. This method is generally applicable to complex systems and might serve to systematically explore the photochem. origin of homochirality. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } We introduce a general theor. approach for the simulation of photochem. dynamics under the influence of circularly polarized light to explore the possibility of generating enantiomeric enrichment through polarized-light-selective photochem. The method is applied to the simulation of the photolysis of alanine, a prototype chiral amino acid. It is shown that a systematic enantiomeric enrichment can be obtained depending on the helicity of the circularly polarized light that induces the excited-state photochem. of alanine. By analyzing the patterns of the photoinduced fragmentation of alanine we find an inducible enantiomeric enrichment up to 1.7%, which is also in good correspondence to the exptl. findings. This method is generally applicable to complex systems and might serve to systematically explore the photochem. origin of homochirality. [on SciFinder(R)] |
10. | Miyazaki, Mitsuhiko; Nakamura, Takashi; Wohlgemuth, Matthias; Mitric, Roland; Dopfer, Otto; Fujii, Masaaki. Single water solvation dynamics in the 4-aminobenzonitrile-water cluster cation revealed by picosecond time-resolved infrared spectroscopy. Journal Article Physical Chemistry Chemical Physics, 17 (44), pp. 29969–29977, 2015, ISSN: 1463-9076. @article{Miyazaki2015, title = {Single water solvation dynamics in the 4-aminobenzonitrile-water cluster cation revealed by picosecond time-resolved infrared spectroscopy.}, author = {Mitsuhiko Miyazaki and Takashi Nakamura and Matthias Wohlgemuth and Roland Mitric and Otto Dopfer and Masaaki. Fujii}, doi = {10.1039/C5CP05400A}, issn = {1463-9076}, year = {2015}, date = {2015-01-01}, journal = {Physical Chemistry Chemical Physics}, volume = {17}, number = {44}, pages = {29969--29977}, publisher = {Royal Society of Chemistry}, abstract = {The dynamics of a solvent is important for many chem. and biol. processes. Here, the migration dynamics of a single water mol. is triggered by the photoionization of the 4-aminobenzonitrile-water (4ABN-W) cluster and monitored in real time by picosecond time-resolved IR (ps TRIR) spectroscopy. In the neutral cluster, water is hydrogen-bonded to the CN group. When this CN-bound cluster is selectively ionized with an excess energy of 1238 cm-1, water migrates with a lifetime of $tau$ = 17 ps from the CN to the NH2 group, forming a more stable 4ABN+-W(NH) isomer with a yield of unity. By decreasing the ionization excess energy, the yield of the CN → NH2 reaction is reduced. The relatively slow migration in comparison to the ionization-induced solvent dynamics in the related acetanilide-water cluster cation ($tau$ = 5 ps) is discussed in terms of the internal excess energy after photoionization and the shape of the potential energy surface. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } The dynamics of a solvent is important for many chem. and biol. processes. Here, the migration dynamics of a single water mol. is triggered by the photoionization of the 4-aminobenzonitrile-water (4ABN-W) cluster and monitored in real time by picosecond time-resolved IR (ps TRIR) spectroscopy. In the neutral cluster, water is hydrogen-bonded to the CN group. When this CN-bound cluster is selectively ionized with an excess energy of 1238 cm-1, water migrates with a lifetime of $tau$ = 17 ps from the CN to the NH2 group, forming a more stable 4ABN+-W(NH) isomer with a yield of unity. By decreasing the ionization excess energy, the yield of the CN → NH2 reaction is reduced. The relatively slow migration in comparison to the ionization-induced solvent dynamics in the related acetanilide-water cluster cation ($tau$ = 5 ps) is discussed in terms of the internal excess energy after photoionization and the shape of the potential energy surface. [on SciFinder(R)] |
9. | Wohlgemuth, Matthias; Miyazaki, Mitsuhiko; Weiler, Martin; Sakai, Makoto; Dopfer, Otto; Fujii, Masaaki; Mitric, Roland. Solvation Dynamics of a Single Water Molecule Probed by Infrared Spectra-Theory Meets Experiment. Journal Article Angewandte Chemie, International Edition, 53 (52), pp. 14601–14604, 2014, ISSN: 1433-7851. @article{Wohlgemuth2014, title = {Solvation Dynamics of a Single Water Molecule Probed by Infrared Spectra-Theory Meets Experiment.}, author = {Matthias Wohlgemuth and Mitsuhiko Miyazaki and Martin Weiler and Makoto Sakai and Otto Dopfer and Masaaki Fujii and Roland. Mitric}, doi = {10.1002/anie.201409047}, issn = {1433-7851}, year = {2014}, date = {2014-01-01}, journal = {Angewandte Chemie, International Edition}, volume = {53}, number = {52}, pages = {14601--14604}, publisher = {Wiley-VCH Verlag GmbH & Co. KGaA}, abstract = {The dynamics and energetics of water at interfaces or in biol. systems plays a fundamental role in all solvation and biol. phenomena in aq. soln. In particular, the migration of water mols. is the first step that controls the overall process in the time domain. Exptl., the dynamics of individual water mols. is nearly impossible to follow in soln., because signals from mols. in heterogeneous environments overlap. Although mol. dynamics simulations do not have this restriction, there is a lack of exptl. data to validate the calcd. dynamics. Here, we demonstrate a new strategy, in which the calcd. dynamics are verified by measured time-resolved IR spectra. The coexistence of fast and slow migrations of water mols. around a CONH peptide linkage is revealed for a model system representative of a hydrate peptide. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } The dynamics and energetics of water at interfaces or in biol. systems plays a fundamental role in all solvation and biol. phenomena in aq. soln. In particular, the migration of water mols. is the first step that controls the overall process in the time domain. Exptl., the dynamics of individual water mols. is nearly impossible to follow in soln., because signals from mols. in heterogeneous environments overlap. Although mol. dynamics simulations do not have this restriction, there is a lack of exptl. data to validate the calcd. dynamics. Here, we demonstrate a new strategy, in which the calcd. dynamics are verified by measured time-resolved IR spectra. The coexistence of fast and slow migrations of water mols. around a CONH peptide linkage is revealed for a model system representative of a hydrate peptide. [on SciFinder(R)] |
8. | Humeniuk, Alexander; Wohlgemuth, Matthias; Suzuki, Toshinori; Mitric, Roland. Time-resolved photoelectron imaging spectra from non-adiabatic molecular dynamics simulations. Journal Article Journal of Chemical Physics, 139 (13), pp. 134104/1–134104/9, 2013, ISSN: 0021-9606. @article{Humeniuk2013, title = {Time-resolved photoelectron imaging spectra from non-adiabatic molecular dynamics simulations.}, author = {Alexander Humeniuk and Matthias Wohlgemuth and Toshinori Suzuki and Roland. Mitric}, doi = {10.1063/1.4820238}, issn = {0021-9606}, year = {2013}, date = {2013-01-01}, journal = {Journal of Chemical Physics}, volume = {139}, number = {13}, pages = {134104/1--134104/9}, publisher = {American Institute of Physics}, abstract = {We present an efficient method for the simulation of time-resolved photoelectron imaging (TRPEI) spectra in polyat. mols. Our approach combines trajectory-based mol. dynamics that account for non-adiabatic effects using surface hopping, with an approx. treatment of the photoionization process using Dyson orbitals as initial and Coulomb waves as final electron states. The method has been implemented in the frame of linear response time-dependent d. functional theory. As an illustration, we simulate time- and energy-resolved anisotropy maps for the furan mol. and compare them with recent exptl. data . Our method can be generally used for the interpretation of TRPEI expts. allowing to shed light into the fundamental photochem. processes in complex mols. (c) 2013 American Institute of Physics. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } We present an efficient method for the simulation of time-resolved photoelectron imaging (TRPEI) spectra in polyat. mols. Our approach combines trajectory-based mol. dynamics that account for non-adiabatic effects using surface hopping, with an approx. treatment of the photoionization process using Dyson orbitals as initial and Coulomb waves as final electron states. The method has been implemented in the frame of linear response time-dependent d. functional theory. As an illustration, we simulate time- and energy-resolved anisotropy maps for the furan mol. and compare them with recent exptl. data . Our method can be generally used for the interpretation of TRPEI expts. allowing to shed light into the fundamental photochem. processes in complex mols. (c) 2013 American Institute of Physics. [on SciFinder(R)] |
7. | 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)] |
6. | 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)] |
5. | 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)] |
4. | Wohlgemuth, Matthias; Bonacic-Koutecky, Vlasta; Mitric, Roland. Journal of Chemical Physics, 135 (5), pp. 054105/1–054105/10, 2011, ISSN: 0021-9606. @article{Wohlgemuth2011, title = {Time-dependent density functional theory excited state nonadiabatic dynamics combined with quantum mechanical/molecular mechanical approach: Photodynamics of indole in water.}, author = {Matthias Wohlgemuth and Vlasta Bonacic-Koutecky and Roland. Mitric}, doi = {10.1063/1.3622563}, issn = {0021-9606}, year = {2011}, date = {2011-01-01}, journal = {Journal of Chemical Physics}, volume = {135}, number = {5}, pages = {054105/1--054105/10}, publisher = {American Institute of Physics}, abstract = {We present a combination of time-dependent d. functional theory with the quantum mech./mol. mech. approach which can be applied to study nonadiabatic dynamical processes in mol. systems interacting with the environment. Our method is illustrated on the example of ultrafast excited state dynamics of indole in water. We compare the mechanisms of nonradiative relaxation and the electronic state lifetimes for isolated indole, indole in a sphere of classical water, and indole + 3H2O embedded in a classical water sphere. In the case of isolated indole, the initial excitation to the S2 electronic state is followed by an ultrafast internal conversion to the S1 state with a time const. of 17 fs. The S1 state is long living ( textgreater 30 ps) and deactivates to the ground state along the N-H stretching coordinate. This deactivation mechanism remains unchanged for indole in a classical water sphere. However, the lifetimes of the S2 and S1 electronic states are extended. The inclusion of three explicit water mols. opens a new relaxation channel which involves the electron transfer to the solvent, leading eventually to the formation of a solvated electron. The relaxation to the ground state takes place on a time scale of 60 fs and contributes to the lowering of the fluorescence quantum yield. Our simulations demonstrate the importance of including explicit water mols. in the theor. treatment of solvated systems. (c) 2011 American Institute of Physics. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } We present a combination of time-dependent d. functional theory with the quantum mech./mol. mech. approach which can be applied to study nonadiabatic dynamical processes in mol. systems interacting with the environment. Our method is illustrated on the example of ultrafast excited state dynamics of indole in water. We compare the mechanisms of nonradiative relaxation and the electronic state lifetimes for isolated indole, indole in a sphere of classical water, and indole + 3H2O embedded in a classical water sphere. In the case of isolated indole, the initial excitation to the S2 electronic state is followed by an ultrafast internal conversion to the S1 state with a time const. of 17 fs. The S1 state is long living ( textgreater 30 ps) and deactivates to the ground state along the N-H stretching coordinate. This deactivation mechanism remains unchanged for indole in a classical water sphere. However, the lifetimes of the S2 and S1 electronic states are extended. The inclusion of three explicit water mols. opens a new relaxation channel which involves the electron transfer to the solvent, leading eventually to the formation of a solvated electron. The relaxation to the ground state takes place on a time scale of 60 fs and contributes to the lowering of the fluorescence quantum yield. Our simulations demonstrate the importance of including explicit water mols. in the theor. treatment of solvated systems. (c) 2011 American Institute of Physics. [on SciFinder(R)] |
3. | 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)] |
2. | 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)] |
1. | Mitric, Roland; Werner, Ute; Wohlgemuth, Matthias; Seifert, Gotthard; Bonacic-Koutecky, Vlasta. Nonadiabatic Dynamics within Time-Dependent Density Functional Tight Binding Method. Journal Article Journal of Physical Chemistry A, 113 (45), pp. 12700–12705, 2009, ISSN: 1089-5639. @article{Mitric2009, title = {Nonadiabatic Dynamics within Time-Dependent Density Functional Tight Binding Method.}, author = {Roland Mitric and Ute Werner and Matthias Wohlgemuth and Gotthard Seifert and Vlasta. Bonacic-Koutecky}, doi = {10.1021/jp905600w}, issn = {1089-5639}, year = {2009}, date = {2009-01-01}, journal = {Journal of Physical Chemistry A}, volume = {113}, number = {45}, pages = {12700--12705}, publisher = {American Chemical Society}, abstract = {A nonadiabatic mol. dynamics is implemented in the framework of the time-dependent d. functional tight binding method (TDDFTB) combined with Tully's stochastic surface hopping algorithm. The applicability of our method to complex mol. systems is illustrated on the example of the ultrafast excited state dynamics of microsolvated adenine. Our results demonstrate that in the presence of water, upon initial excitation to the S3 ($pi$-$pi$*) state at 260 nm, an ultrafast relaxation to the S1 state with a time const. of 16 fs is induced, followed by the radiationless decay to the ground state with a time const. of 200 fs. [on SciFinder(R)]}, keywords = {}, pubstate = {published}, tppubtype = {article} } A nonadiabatic mol. dynamics is implemented in the framework of the time-dependent d. functional tight binding method (TDDFTB) combined with Tully's stochastic surface hopping algorithm. The applicability of our method to complex mol. systems is illustrated on the example of the ultrafast excited state dynamics of microsolvated adenine. Our results demonstrate that in the presence of water, upon initial excitation to the S3 ($pi$-$pi$*) state at 260 nm, an ultrafast relaxation to the S1 state with a time const. of 16 fs is induced, followed by the radiationless decay to the ground state with a time const. of 200 fs. [on SciFinder(R)] |