1
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Cavaletto SM, Nam Y, Rouxel JR, Keefer D, Yong H, Mukamel S. Attosecond Monitoring of Nonadiabatic Molecular Dynamics by Transient X-ray Transmission Spectroscopy. J Chem Theory Comput 2023; 19:2327-2339. [PMID: 37015111 DOI: 10.1021/acs.jctc.3c00062] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2023]
Abstract
Tracing the evolution of molecular coherences can provide a direct, unambiguous probe of nonadiabatic molecular processes, such as the passage through conical intersections of electronic states. Two techniques, attosecond transient absorption spectroscopy (ATAS) and Transient Redistribution of Ultrafast Electronic Coherences in Attosecond Raman Signals (TRUECARS), have been used or proposed for monitoring nonadiabatic molecular dynamics. Both techniques employ the transmission of a weak attosecond extreme-ultraviolet or X-ray probe to interrogate the molecule at controllable time delays with respect to an optical pump, thereby extracting dynamical information from transient spectral features. The connection between these techniques has not been firmly established yet. In this theoretical study, we provide a unified description of both transient transmission techniques, establishing their relationship as limits of the same pump-probe spectroscopy technique for different pulse parameter regimes. We demonstrate this by quantum dynamical simulations of thiophenol photodissociation and show how complementary coherence information can be revealed by the two techniques.
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Affiliation(s)
- Stefano M Cavaletto
- Department of Chemistry and Department of Physics & Astronomy, University of California Irvine, Irvine, California 92697, United States
| | - Yeonsig Nam
- Department of Chemistry and Department of Physics & Astronomy, University of California Irvine, Irvine, California 92697, United States
| | - Jérémy R Rouxel
- Department of Chemistry and Department of Physics & Astronomy, University of California Irvine, Irvine, California 92697, United States
- Université de Lyon, UJM-Saint-Étienne, CNRS, IOGS, Laboratoire Hubert Curien UMR 5516, Saint-Étienne 42023, France
| | - Daniel Keefer
- Department of Chemistry and Department of Physics & Astronomy, University of California Irvine, Irvine, California 92697, United States
| | - Haiwang Yong
- Department of Chemistry and Department of Physics & Astronomy, University of California Irvine, Irvine, California 92697, United States
| | - Shaul Mukamel
- Department of Chemistry and Department of Physics & Astronomy, University of California Irvine, Irvine, California 92697, United States
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2
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Yong H, Rouxel JR, Keefer D, Mukamel S. Direct Monitoring of Conical Intersection Passage via Electronic Coherences in Twisted X-Ray Diffraction. PHYSICAL REVIEW LETTERS 2022; 129:103001. [PMID: 36112435 DOI: 10.1103/physrevlett.129.103001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 04/07/2022] [Accepted: 08/05/2022] [Indexed: 06/15/2023]
Abstract
Quantum coherences in electronic motions play a critical role in determining the pathways and outcomes of virtually all photophysical and photochemical molecular processes. However, the direct observation of electronic coherences in the vicinity of conical intersections remains a formidable challenge. We propose a novel time-resolved twisted x-ray diffraction technique that can directly monitor the electronic coherences created as the molecule passes through a conical intersection. We show that the contribution of electronic populations to this signal is canceled out when using twisted x-ray beams that carry a light orbital angular momentum, providing a direct measurement of transient electronic coherences in gas-phase molecules.
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Affiliation(s)
- Haiwang Yong
- Department of Chemistry, University of California, Irvine, California 92697, USA
- Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
| | - Jérémy R Rouxel
- University Lyon, UJM-Saint-Étienne, CNRS, Graduate School Optics Institute, Laboratoire Hubert Curien UMR 5516, Saint-Étienne 42023, France
| | - Daniel Keefer
- Department of Chemistry, University of California, Irvine, California 92697, USA
- Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
| | - Shaul Mukamel
- Department of Chemistry, University of California, Irvine, California 92697, USA
- Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
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3
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Nam Y, Montorsi F, Keefer D, Cavaletto SM, Lee JY, Nenov A, Garavelli M, Mukamel S. Time-Resolved Optical Pump-Resonant X-ray Probe Spectroscopy of 4-Thiouracil: A Simulation Study. J Chem Theory Comput 2022; 18:3075-3088. [PMID: 35476905 DOI: 10.1021/acs.jctc.2c00064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We theoretically monitor the photoinduced ππ* → nπ* internal conversion process in 4-thiouracil (4TU), triggered by an optical pump. The element-sensitive spectroscopic signatures are recorded by a resonant X-ray probe tuned to the sulfur, oxygen, or nitrogen K-edge. We employ high-level electronic structure methods optimized for core-excited electronic structure calculation combined with quantum nuclear wavepacket dynamics computed on two relevant nuclear modes, fully accounting for their quantum nature of nuclear motions. We critically discuss the capabilities and limitations of the resonant technique. For sulfur and nitrogen, we document a pre-edge spectral window free from ground-state background and rich with ππ* and nπ* absorption features. The lowest sulfur K-edge shows strong absorption for both ππ* and nπ*. In the lowest nitrogen K-edge window, we resolve a state-specific fingerprint of the ππ* and an approximate timing of the conical intersection via its depletion. A spectral signature of the nπ* transition, not accessible by UV-vis spectroscopy, is identified. The oxygen K-edge is not sensitive to molecular deformations and gives steady transient absorption features without spectral dynamics. The ππ*/nπ* coherence information is masked by more intense contributions from populations. Altogether, element-specific time-resolved resonant X-ray spectroscopy provides a detailed picture of the electronic excited-state dynamics and therefore a sensitive window into the photophysics of thiobases.
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Affiliation(s)
- Yeonsig Nam
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States.,Convergence Research Center for Energy and Environmental Sciences, Sungkyunkwan University, Suwon 16419, Korea
| | - Francesco Montorsi
- Dipartimento di Chimica Industriale "Toso Montanari", Universita' degli Studi di Bologna, I-40136 Bologna, Italy
| | - Daniel Keefer
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Stefano M Cavaletto
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Jin Yong Lee
- Convergence Research Center for Energy and Environmental Sciences, Sungkyunkwan University, Suwon 16419, Korea.,Department of Chemistry, Sungkyunkwan University, Suwon 16419, Korea
| | - Artur Nenov
- Dipartimento di Chimica Industriale "Toso Montanari", Universita' degli Studi di Bologna, I-40136 Bologna, Italy
| | - Marco Garavelli
- Dipartimento di Chimica Industriale "Toso Montanari", Universita' degli Studi di Bologna, I-40136 Bologna, Italy
| | - Shaul Mukamel
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
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4
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Rouxel JR, Keefer D, Aleotti F, Nenov A, Garavelli M, Mukamel S. Coupled Electronic and Nuclear Motions during Azobenzene Photoisomerization Monitored by Ultrafast Electron Diffraction. J Chem Theory Comput 2022; 18:605-613. [DOI: 10.1021/acs.jctc.1c00792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jérémy R. Rouxel
- Department of Chemistry and Physics & Astronomy, University of California, Irvine, California 92697-2025, United States
- Univ Lyon, UJM-Saint-Etienne, CNRS, Graduate School Optics Institute, Laboratoire Hubert Curien UMR 5516, Saint-Etienne, F-42023, France
| | - Daniel Keefer
- Department of Chemistry and Physics & Astronomy, University of California, Irvine, California 92697-2025, United States
| | - Flavia Aleotti
- Dipartimento di Chimica Industriale, Universitá degli Studi di Bologna, Viale del Risorgimento 4, Bologna, I-40136, Italy
| | - Artur Nenov
- Dipartimento di Chimica Industriale, Universitá degli Studi di Bologna, Viale del Risorgimento 4, Bologna, I-40136, Italy
| | - Marco Garavelli
- Dipartimento di Chimica Industriale, Universitá degli Studi di Bologna, Viale del Risorgimento 4, Bologna, I-40136, Italy
| | - Shaul Mukamel
- Department of Chemistry and Physics & Astronomy, University of California, Irvine, California 92697-2025, United States
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5
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Keefer D, Rouxel JR, Aleotti F, Segatta F, Garavelli M, Mukamel S. Diffractive Imaging of Conical Intersections Amplified by Resonant Infrared Fields. J Am Chem Soc 2021; 143:13806-13815. [PMID: 34402612 DOI: 10.1021/jacs.1c06068] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The fate of virtually all photochemical reactions is determined by conical intersections. These are energetically degenerate regions of molecular potential energy surfaces that strongly couple electronic states, thereby enabling fast relaxation channels. Their direct spectroscopic detection relies on weak features that are often buried beneath stronger, less interesting contributions. For azobenzene photoisomerization, a textbook photochemical reaction, we demonstrate how a resonant infrared field can be employed during the conical intersection passage to significantly enhance its coherence signatures in time-resolved X-ray diffraction while leaving the product yield intact. This transition-state amplification holds promise to bring signals of conical intersections above the detection threshold.
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Affiliation(s)
- Daniel Keefer
- Departments of Chemistry and Physics & Astronomy, University of California, Irvine, California 92697-2025, United States
| | - Jérémy R Rouxel
- University Lyon, UJM-Saint-Étienne, CNRS, Graduate School Optics Institute, Laboratoire Hubert Curien UMR 5516, Saint-Étienne 42023, France
| | - Flavia Aleotti
- Dipartimento di Chimica Industriale, Università degli Studi di Bologna, Viale del Risorgimento 4, I-40136 Bologna, Italy
| | - Francesco Segatta
- Dipartimento di Chimica Industriale, Università degli Studi di Bologna, Viale del Risorgimento 4, I-40136 Bologna, Italy
| | - Marco Garavelli
- Dipartimento di Chimica Industriale, Università degli Studi di Bologna, Viale del Risorgimento 4, I-40136 Bologna, Italy
| | - Shaul Mukamel
- Departments of Chemistry and Physics & Astronomy, University of California, Irvine, California 92697-2025, United States
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6
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Cavaletto SM, Keefer D, Rouxel JR, Aleotti F, Segatta F, Garavelli M, Mukamel S. Unveiling the spatial distribution of molecular coherences at conical intersections by covariance X-ray diffraction signals. Proc Natl Acad Sci U S A 2021; 118:e2105046118. [PMID: 34050030 PMCID: PMC8179141 DOI: 10.1073/pnas.2105046118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The outcomes and timescales of molecular nonadiabatic dynamics are decisively impacted by the quantum coherences generated at localized molecular regions. In time-resolved X-ray diffraction imaging, these coherences create distinct signatures via inelastic photon scattering, but they are buried under much stronger background elastic features. Here, we exploit the rich dynamical information encoded in the inelastic patterns, which we reveal by frequency-dispersed covariance ultrafast powder X-ray diffraction of stochastic X-ray free-electron laser pulses. This is demonstrated for the photoisomerization of azobenzene involving the passage through a conical intersection, where the nuclear wave packet branches and explores different quantum pathways. Snapshots of the coherence dynamics are obtained at high frequency shifts, not accessible with conventional diffraction measurements. These provide access to the timing and to the confined spatial distribution of the valence electrons directly involved in the conical intersection passage. This study can be extended to full three-dimensional imaging of conical intersections with ultrafast X-ray and electron diffraction.
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Affiliation(s)
- Stefano M Cavaletto
- Department of Chemistry, University of California, Irvine, CA 92697
- Department of Physics & Astronomy, University of California, Irvine, CA 92697
| | - Daniel Keefer
- Department of Chemistry, University of California, Irvine, CA 92697
- Department of Physics & Astronomy, University of California, Irvine, CA 92697
| | - Jérémy R Rouxel
- Department of Chemistry, University of California, Irvine, CA 92697
- Department of Physics & Astronomy, University of California, Irvine, CA 92697
- University Lyon, UJM-Saint-Étienne, CNRS, Graduate School Optics Institute, Laboratoire Hubert Curien UMR 5516, Saint-Étienne 42023, France
| | - Flavia Aleotti
- Dipartimento di Chimica Industriale, Università degli Studi di Bologna, 40136 Bologna, Italy
| | - Francesco Segatta
- Dipartimento di Chimica Industriale, Università degli Studi di Bologna, 40136 Bologna, Italy
| | - Marco Garavelli
- Dipartimento di Chimica Industriale, Università degli Studi di Bologna, 40136 Bologna, Italy
| | - Shaul Mukamel
- Department of Chemistry, University of California, Irvine, CA 92697;
- Department of Physics & Astronomy, University of California, Irvine, CA 92697
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7
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Imaging conical intersection dynamics during azobenzene photoisomerization by ultrafast X-ray diffraction. Proc Natl Acad Sci U S A 2021; 118:2022037118. [PMID: 33436412 DOI: 10.1073/pnas.2022037118] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
X-ray diffraction is routinely used for structure determination of stationary molecular samples. Modern X-ray photon sources, e.g., from free-electron lasers, enable us to add temporal resolution to these scattering events, thereby providing a movie of atomic motions. We simulate and decipher the various contributions to the X-ray diffraction pattern for the femtosecond isomerization of azobenzene, a textbook photochemical process. A wealth of information is encoded besides real-time monitoring of the molecular charge density for the cis to trans isomerization. In particular, vibronic coherences emerge at the conical intersection, contributing to the total diffraction signal by mixed elastic and inelastic photon scattering. They cause distinct phase modulations in momentum space, which directly reflect the real-space phase modulation of the electronic transition density during the nonadiabatic passage. To overcome the masking by the intense elastic scattering contributions from the electronic populations in the total diffraction signal, we discuss how this information can be retrieved, e.g., by employing very hard X-rays to record large scattering momentum transfers.
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8
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Visualizing conical intersection passages via vibronic coherence maps generated by stimulated ultrafast X-ray Raman signals. Proc Natl Acad Sci U S A 2020; 117:24069-24075. [PMID: 32929028 DOI: 10.1073/pnas.2015988117] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The rates and outcomes of virtually all photophysical and photochemical processes are determined by conical intersections. These are regions of degeneracy between electronic states on the nuclear landscape of molecules where electrons and nuclei evolve on comparable timescales and thus become strongly coupled, enabling radiationless relaxation channels upon optical excitation. Due to their ultrafast nature and vast complexity, monitoring conical intersections experimentally is an open challenge. We present a simulation study on the ultrafast photorelaxation of uracil, based on a quantum description of the nuclei. We demonstrate an additional window into conical intersections obtained by recording the transient wavepacket coherence during this passage with an X-ray free-electron laser pulse. Two major findings are reported. First, we find that the vibronic coherence at the conical intersection lives for several hundred femtoseconds and can be measured during this entire time. Second, the time-dependent energy-splitting landscape of the participating vibrational and electronic states is directly extracted from Wigner spectrograms of the signal. These offer a physical picture of the quantum conical intersection pathways through visualizing their transient vibronic coherence distributions. The path of a nuclear wavepacket in the vicinity of the conical intersection is directly mapped by the proposed experiment.
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9
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Roos MK, Reiter S, de Vivie-Riedle R. Ultrafast relaxation from 1La to 1Lb in pyrene: a theoretical study. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.08.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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10
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Abstract
In 1998, the first successful quantum control experiment with application to a molecular framework was conducted with a shaped laser pulse, optimizing the branching ratio between different organometallic reaction channels. This work induced a vast activity in quantum control during the next 10 years, and different optimization aims were achieved in the gas phase, liquid phase, and even in biologically relevant molecules like light-harvesting complexes. Accompanying and preceding this development were important advances in theoretical quantum control simulations. They predicted several control scenarios and explained how and why quantum control experiments work. After many successful proofs of concept in molecular science, the big challenge is to expand its huge conceptual potential of directly being able to steer nuclear and/or electronic motion to more applied implementations. In this Account, based on several recent advances, we give a personal evaluation of where the field of molecular quantum control is at the moment and especially where we think promising applications can be in the near future. One of these paths leads to synthetic chemistry. The synthesis of novel pharmaceutical compounds or natural products often involves many synthetic steps, each one devouring resources and lowering the product yield. Shaped laser pulses can possibly act as photonic reagents and shorten the synthetic route toward the desired product. Chemical synthesis usually takes place in solution, and by including explicit solvent molecules in our quantum control simulations, we were able to identify their highly inhomogeneous influence on chemical reactions and how this affects potential quantum control. More important, we demonstrated for a synthetically relevant example that these complications can be overcome in theory, and laser pulses can be optimized to initiate the desired carbon-carbon bond formation. Putting this into context with the recently emerging concept of flow chemistry, which brings several practical advantages to the application of laser pulses, we want to encourage experimental groups to exploit this concept. Another path was opened by several additions to the commonly used laser pulse optimization algorithm (optimal control theory, OCT), several of which were developed in our group. The OCT algorithm as such is a purely mathematical optimization procedure, with no direct relation to experimental requirements. This means that usually the electric fields obtained out of OCT optimizations do not resemble laser pulses that can be achieved experimentally. However, the previously mentioned additions are aimed at closing the gap toward the experiment. In a recent quantum control study of our group, these algorithmic developments came to fruition. We were able to suggest a shaped laser pulse which can induce a long-living wave packet in the excited state of uracil. This might pave the way for novel experiments dedicated to investigating the formation of biological photodamage in DNA and RNA. The pulse we suggest is surprisingly simple because of the extended OCT algorithm and fulfills all criteria to be experimentally accessible.
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Affiliation(s)
- Daniel Keefer
- Department Chemie, Ludwig-Maximilians-Universität München, D-81377 München, Germany
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11
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Schüppel F, Roos MK, de Vivie-Riedle R. Ultrafast non-adiabatic dynamics of excited diphenylmethyl bromide elucidated by quantum dynamics and semi-classical on-the-fly dynamics. Phys Chem Chem Phys 2018; 20:22753-22761. [PMID: 30140797 DOI: 10.1039/c8cp03257b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Carbocations and carboradicals are key intermediates in organic chemistry. Typically UV laser excitation is used to induce homolytical or heterolytical bond cleavage in suitable precursor molecules. Of special interest hereby are diphenylmethyl compounds (Ph2CH-X) with X = Cl, Br as a leaving group as they form diphenylmethyl radicals (Ph2CH˙) and cations (Ph2CH+) within a femtosecond time scale in polar solvents. In this work, we build on our methodology developed for the chlorine case and investigate the photodissociation reaction of Ph2CH-Br by state-of-the-art theoretical methods. On the one hand, we employ specially adapted reactive coordinates for a grid-based wave packet dynamics in reduced dimensionality using the Wilson G-matrix ansatz for the kinetic part of the Hamiltonian. On the other hand, we use full-dimensional semiclassical on-the-fly dynamics with Tully's fewest switches surface hopping routine for comparison. We apply both methods to explain remarkable differences in experimental transient absorption measurements for Cl or Br as the leaving group. The wave packet motion, visible only for the bromine leaving group, can be related to the crucial role of the central carbon atom, which undergoes rehybridization from sp3 to sp2 during the photoinduced bond cleavage. Comparable features are the two consecutive conical intersections near the Franck-Condon region controlling the product splitting to Ph2CH˙/Br˙ and Ph2CH+/Br- as well as the difference in delay time for the respective product formation.
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Affiliation(s)
- Franziska Schüppel
- Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 Munich, Germany.
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12
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Zauleck JPP, de Vivie-Riedle R. Constructing Grids for Molecular Quantum Dynamics Using an Autoencoder. J Chem Theory Comput 2017; 14:55-62. [DOI: 10.1021/acs.jctc.7b01045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Julius P. P. Zauleck
- Department Chemie, Ludwig-Maximilians-Universität München, D-81377 München, Germany
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13
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Steffen J, Hartke B. Cheap but accurate calculation of chemical reaction rate constants from ab initio data, via system-specific, black-box force fields. J Chem Phys 2017; 147:161701. [DOI: 10.1063/1.4979712] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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14
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Kowalewski M, Fingerhut BP, Dorfman KE, Bennett K, Mukamel S. Simulating Coherent Multidimensional Spectroscopy of Nonadiabatic Molecular Processes: From the Infrared to the X-ray Regime. Chem Rev 2017; 117:12165-12226. [DOI: 10.1021/acs.chemrev.7b00081] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Markus Kowalewski
- Department
of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California 92697-2025, United States
| | - Benjamin P. Fingerhut
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, D-12489 Berlin, Germany
| | - Konstantin E. Dorfman
- State
Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Kochise Bennett
- Department
of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California 92697-2025, United States
| | - Shaul Mukamel
- Department
of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California 92697-2025, United States
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15
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Riedle E, Roos MK, Thallmair S, Sailer CF, Krebs N, Fingerhut BP, de Vivie-Riedle R. Ultrafast photochemistry with two product channels: Wavepacket motion through two distinct conical intersections. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.02.086] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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16
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Keefer D, Thallmair S, Matsika S, de Vivie-Riedle R. Controlling Photorelaxation in Uracil with Shaped Laser Pulses: A Theoretical Assessment. J Am Chem Soc 2017; 139:5061-5066. [DOI: 10.1021/jacs.6b12033] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Daniel Keefer
- Department
Chemie, Ludwig-Maximilians-Universität München, D-81377 München, Germany
| | - Sebastian Thallmair
- Department
Chemie, Ludwig-Maximilians-Universität München, D-81377 München, Germany
| | - Spiridoula Matsika
- Department
of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
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17
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Zauleck JPP, Thallmair S, Loipersberger M, de Vivie-Riedle R. Two New Methods To Generate Internal Coordinates for Molecular Wave Packet Dynamics in Reduced Dimensions. J Chem Theory Comput 2016; 12:5698-5708. [PMID: 27951675 DOI: 10.1021/acs.jctc.6b00800] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The curse of dimensionality still remains as the central challenge of molecular quantum dynamical calculations. Either compromises on the accuracy of the potential landscape have to be made or methods must be used that reduce the dimensionality of the configuration space of molecular systems to a low dimensional one. For dynamic approaches such as grid-based wave packet dynamics that are confined to a small number of degrees of freedom this dimensionality reduction can become a major part of the overall problem. A common strategy to reduce the configuration space is by selection of a set of internal coordinates using chemical intuition. We devised two methods that increase the degree of automation of the dimensionality reduction as well as replace chemical intuition by more quantifiable criteria. Both methods reduce the dimensionality linearly and use the intrinsic reaction coordinate as guidance. The first one solely relies on the intrinsic reaction coordinate (IRC), whereas the second one uses semiclassical trajectories to identify the important degrees of freedom.
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Affiliation(s)
- Julius P P Zauleck
- Department Chemie, Ludwig-Maximilians-Universität München , D-81377 München, Germany
| | - Sebastian Thallmair
- Department Chemie, Ludwig-Maximilians-Universität München , D-81377 München, Germany
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