1
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Worth GA, Robb MA. Controlling Electronic Coherences and the Curvature Induced by the Derivative Coupling at a Conical Intersection: A Quantum Ehrenfest (QuEh) Protocol for Reaction Path Following Application to "Channel 3" Benzene Photochemistry. J Phys Chem A 2024; 128:5408-5415. [PMID: 38917388 PMCID: PMC11247493 DOI: 10.1021/acs.jpca.4c02449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2024]
Abstract
We report a protocol for the implementation of "reaction path following" from a transition state through a conical intersection, including both the path curvature induced by the derivative coupling and the corresponding induced electronic coherences. This protocol focuses on the "central" Gaussian wavepacket (initially unexcited) in the quantum Ehrenfest (QuEh) method. Like the reaction path following, the normal mode corresponding to the imaginary frequency at the transition state is given an initial momentum. The protocol is applied to the "channel 3" radiationless decay of benzene. We also demonstrate that one can enhance the effect of the derivative coupling and the electronic coherence with an IR pulse.
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Affiliation(s)
- Graham A Worth
- Department of Chemistry, University College London, 20, Gordon Street, WC1H 0AJ London, U.K
| | - Michael A Robb
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, 80 Wood Lane, W12 0BZ London, U.K
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2
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Villaseco Arribas E, Maitra NT, Agostini F. Nonadiabatic dynamics with classical trajectories: The problem of an initial coherent superposition of electronic states. J Chem Phys 2024; 160:054102. [PMID: 38310471 DOI: 10.1063/5.0186984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 01/11/2024] [Indexed: 02/05/2024] Open
Abstract
Advances in coherent light sources and development of pump-probe techniques in recent decades have opened the way to study electronic motion in its natural time scale. When an ultrashort laser pulse interacts with a molecular target, a coherent superposition of electronic states is created and the triggered electron dynamics is coupled to the nuclear motion. A natural and computationally efficient choice to simulate this correlated dynamics is a trajectory-based method where the quantum-mechanical electronic evolution is coupled to a classical-like nuclear dynamics. These methods must approximate the initial correlated electron-nuclear state by associating an initial electronic wavefunction to each classical trajectory in the ensemble. Different possibilities exist that reproduce the initial populations of the exact molecular wavefunction when represented in a basis. We show that different choices yield different dynamics and explore the effect of this choice in Ehrenfest, surface hopping, and exact-factorization-based coupled-trajectory schemes in a one-dimensional two-electronic-state model system that can be solved numerically exactly. This work aims to clarify the problems that standard trajectory-based techniques might have when a coherent superposition of electronic states is created to initialize the dynamics, to discuss what properties and observables are affected by different choices of electronic initial conditions and to point out the importance of quantum-momentum-induced electronic transitions in coupled-trajectory schemes.
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Affiliation(s)
- Evaristo Villaseco Arribas
- Department of Physics, Rutgers University, Newark, New Jersey 07102, USA
- Université Paris-Saclay, CNRS, Institut de Chimie Physique UMR8000, 91405 Orsay, France
| | - Neepa T Maitra
- Department of Physics, Rutgers University, Newark, New Jersey 07102, USA
| | - Federica Agostini
- Université Paris-Saclay, CNRS, Institut de Chimie Physique UMR8000, 91405 Orsay, France
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3
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Wenzel M, Mitric R. Prediction of fluorescence quantum yields using the extended thawed Gaussian approximation. J Chem Phys 2023; 159:234113. [PMID: 38108487 DOI: 10.1063/5.0178106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 11/26/2023] [Indexed: 12/19/2023] Open
Abstract
Spontaneous emission and internal conversion rates are calculated within harmonic approximations and compared to the results obtained within the semi-classical extended thawed Gaussian approximation (ETGA). This is the first application of the ETGA in the calculation of internal conversion and emission rates for real molecular systems, namely, formaldehyde, fluorobenzene, azulene, and a dicyano-squaraine dye. The viability of the models as black-box tools for prediction of spontaneous emission and internal conversion rates is assessed. All calculations were done using a consistent protocol in order to investigate how different methods perform without previous experimental knowledge using density functional theory (DFT) and time-dependent DFT (TD-DFT) with B3LYP, PBE0, ωB97XD, and CAM-B3LYP functionals. Contrasting the results with experimental data shows that there are further improvements required before theoretical predictions of emission and internal conversion rates can be used as reliable indicators for the photo-luminescence properties of molecules. We find that the ETGA performs rather similar to the vertical harmonical model. Including anharmonicities in the calculation of internal conversion rates has a moderate effect on the quantitative results in the studied systems. The emission rates are fairly stable with respect to computational parameters, but the internal conversion rate reveals itself to be highly dependent on the choice of the spectral line shape function, particularly the width of the Lorentzian function, associated with homogeneous broadening.
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Affiliation(s)
- Michael Wenzel
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Emil-Fischer Str. 42, 97074 Würzburg, Germany
| | - Roland Mitric
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Emil-Fischer Str. 42, 97074 Würzburg, Germany
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4
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Danilov D, Jenkins AJ, Bearpark MJ, Worth GA, Robb MA. Coherent Mixing of Singlet and Triplet States in Acrolein and Ketene: A Computational Strategy for Simulating the Electron-Nuclear Dynamics of Intersystem Crossing. J Phys Chem Lett 2023:6127-6134. [PMID: 37364275 DOI: 10.1021/acs.jpclett.3c01187] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
We present a theoretical study of intersystem crossing (ISC) in acrolein and ketene with the Ehrenfest method that can describe a superposition of singlet and triplet states. Our simulations illustrate a new mechanistic effect of ISC, namely, that a superposition of singlets and triplets yields nonadiabatic dynamics characteristic of that superposition rather than the constituent state potential energy surfaces. This effect is particularly significant in ketene, where mixing of singlet and triplet states along the approach to a singlet/singlet conical intersection occurs, with the spin-orbit coupling (SOC) remaining small throughout. In both cases, the effects require many recrossings of the singlet/triplet state crossing seam, consistent with the textbook treatment of ISC.
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Affiliation(s)
- Don Danilov
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, 82 Wood Lane, W12 0BZ London, United Kingdom
| | - Andrew J Jenkins
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Michael J Bearpark
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, 82 Wood Lane, W12 0BZ London, United Kingdom
| | - Graham A Worth
- Department of Chemistry, University College London, 20 Gordon St., WC1H 0AJ London, United Kingdom
| | - Michael A Robb
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, 82 Wood Lane, W12 0BZ London, United Kingdom
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5
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Wu X, Wen S, Song H, Frauenheim T, Tretiak S, Yam C, Zhang Y. Nonadiabatic Molecular Dynamics Simulations Based on Time-Dependent Density Functional Tight-Binding Method. J Chem Phys 2022; 157:084114. [DOI: 10.1063/5.0100339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Nonadiabatic excited-state molecular dynamics underpin many photophysical and photochemical phenomena, such as exciton dynamics, charge separation and transport. In this work, we present an efficient nonadiabatic molecular dynamic (NAMD) simulation method based on time-dependent density functional tight-binding (TDDFTB) theory. Specifically, the adiabatic electronic structure, an essential NAMD input, is described at the TDDFTB level. The nonadiabatic effects originating from the coupled motions of electrons and nuclei are treated by the trajectory surface hopping algorithm. To improve the computational efficiency, nonadiabatic couplings between excited states within the TDDFTB method are derived and implemented using an analytical approach. Further, the time-dependent nonadiabatic coupling scalars are calculated based on the overlap between molecular orbitals rather than the Slater determinants to speed up the simulations. In addition, the electronic decoherence scheme and a state reassigned unavoided crossings algorithm, which has been implemented in the NEXMD software, are used to improve the accuracy of the simulated dynamics and handle trivial unavoided crossings. Finally, the photoinduced nonadiabatic dynamics of a benzene molecule are simulated to demonstrate our implementation. The results for excited state NAMD simulations of benzene molecule based on TDDFTB method compare well that obtained with numerically expensive time-dependent density functional theory. The proposed methodology provides an attractive theoretical simulation tool for predicting the photophysical and photochemical properties of complex materials.
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Affiliation(s)
- Xiaoyan Wu
- Shenzhen JL Computational Science and Applied Research Institute, Shenzhen JL Computational Science and Applied Research Institute, China
| | | | - Huajing Song
- Los Alamos National Laboratory, United States of America
| | | | - Sergei Tretiak
- Theoretical Division, T-1, Los Alamos National Laboratory, United States of America
| | - ChiYung Yam
- Beijing Computational Science Research Center, Beijing Computational Science Research Center, China
| | - Yu Zhang
- Theoretical Division, Los Alamos National Laboratory, United States of America
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6
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Koessler ER, Mandal A, Huo P. Incorporating Lindblad Decay Dynamics into Mixed Quantum-Classical Simulations. J Chem Phys 2022; 157:064101. [DOI: 10.1063/5.0099922] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We derive the $\mathcal{L}$-MFE method to incorporate Lindblad jump operator dynamics into the mean-field Ehrenfest (MFE) approach. We map the density matrix evolution of Lindblad dynamics onto pure state coefficients using trajectory averages. We use simple assumptions to construct the $\mathcal{L}$-MFE method that satisfies this exact mapping. This establishes a method that uses independent trajectories which exactly reproduces Lindblad decay dynamics using a wavefunction description, with deterministic changes of the magnitudes of the quantum expansion coefficients, while only adding on a stochastic phase. We further demonstrate that when including nuclei in the Ehrenfest dynamics, the $\mathcal{L}$-MFE method gives semi-quantitatively accurate results, with the accuracy limited by the accuracy of the approximations present in the semiclassical MFE approach. This work provides a general framework to incorporate Lindblad dynamics into semiclassical or mixed quantum-classical simulations.
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Affiliation(s)
- Eric R Koessler
- Chemistry, University of Rochester, United States of America
| | | | - Pengfei Huo
- Department of Chemsitry, University of Rochester Department of Chemistry, United States of America
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7
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Danilov D, Tran T, Bearpark MJ, Marangos JP, Worth GA, Robb MA. How electronic superpositions drive nuclear motion following the creation of a localized hole in the glycine radical cation. J Chem Phys 2022; 156:244114. [DOI: 10.1063/5.0093780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this work, we have studied the nuclear and electron dynamics in the glycine cation starting from localized hole states using the quantum Ehrenfest method. The nuclear dynamics is controlled both by the initial gradient and by the instantaneous gradient that results from the oscillatory electron dynamics (charge migration). We have used the Fourier transform (FT) of the spin densities to identify the “normal modes” of the electron dynamics. We observe an isomorphic relationship between the electron dynamics normal modes and the nuclear dynamics, seen in the vibrational normal modes. The FT spectra obtained this way show bands that are characteristic of the energy differences between the adiabatic hole states. These bands contain individual peaks that are in one-to-one correspondence with atom pair (+·) ↔ (·+) resonances, which, in turn, stimulate nuclear motion involving the atom pair. With such understanding, we anticipate “designer” coherent superpositions that can drive nuclear motion in a particular direction.
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Affiliation(s)
- Don Danilov
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, 82 Wood Lane, W12 0BZ London, United Kingdom
| | - Thierry Tran
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, 82 Wood Lane, W12 0BZ London, United Kingdom
- Department of Chemistry, University College London, 20 Gordon St., WC1H 0AJ London, United Kingdom
| | - Michael J. Bearpark
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, 82 Wood Lane, W12 0BZ London, United Kingdom
| | - Jon P. Marangos
- Department of Physics, Imperial College London, Blackett Lab, Prince Consort Road, SW7 2BW London, United Kingdom
| | - Graham A. Worth
- Department of Chemistry, University College London, 20 Gordon St., WC1H 0AJ London, United Kingdom
| | - Michael A. Robb
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, 82 Wood Lane, W12 0BZ London, United Kingdom
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8
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Mukherjee S, Pinheiro M, Demoulin B, Barbatti M. Simulations of molecular photodynamics in long timescales. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2022; 380:20200382. [PMID: 35341303 PMCID: PMC8958277 DOI: 10.1098/rsta.2020.0382] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/12/2021] [Indexed: 05/04/2023]
Abstract
Nonadiabatic dynamics simulations in the long timescale (much longer than 10 ps) are the next challenge in computational photochemistry. This paper delimits the scope of what we expect from methods to run such simulations: they should work in full nuclear dimensionality, be general enough to tackle any type of molecule and not require unrealistic computational resources. We examine the main methodological challenges we should venture to advance the field, including the computational costs of the electronic structure calculations, stability of the integration methods, accuracy of the nonadiabatic dynamics algorithms and software optimization. Based on simulations designed to shed light on each of these issues, we show how machine learning may be a crucial element for long time-scale dynamics, either as a surrogate for electronic structure calculations or aiding the parameterization of model Hamiltonians. We show that conventional methods for integrating classical equations should be adequate to extended simulations up to 1 ns and that surface hopping agrees semiquantitatively with wave packet propagation in the weak-coupling regime. We also describe our optimization of the Newton-X program to reduce computational overheads in data processing and storage. This article is part of the theme issue 'Chemistry without the Born-Oppenheimer approximation'.
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Affiliation(s)
| | - Max Pinheiro
- Aix Marseille University, CNRS, ICR, Marseille, France
| | | | - Mario Barbatti
- Aix Marseille University, CNRS, ICR, Marseille, France
- Institut Universitaire de France, 75231 Paris, France
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9
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Choi S, Vaníček J. High-order geometric integrators for representation-free Ehrenfest dynamics. J Chem Phys 2021; 155:124104. [PMID: 34598577 DOI: 10.1063/5.0061878] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Ehrenfest dynamics is a useful approximation for ab initio mixed quantum-classical molecular dynamics that can treat electronically nonadiabatic effects. Although a severe approximation to the exact solution of the molecular time-dependent Schrödinger equation, Ehrenfest dynamics is symplectic, is time-reversible, and conserves exactly the total molecular energy as well as the norm of the electronic wavefunction. Here, we surpass apparent complications due to the coupling of classical nuclear and quantum electronic motions and present efficient geometric integrators for "representation-free" Ehrenfest dynamics, which do not rely on a diabatic or adiabatic representation of electronic states and are of arbitrary even orders of accuracy in the time step. These numerical integrators, obtained by symmetrically composing the second-order splitting method and exactly solving the kinetic and potential propagation steps, are norm-conserving, symplectic, and time-reversible regardless of the time step used. Using a nonadiabatic simulation in the region of a conical intersection as an example, we demonstrate that these integrators preserve the geometric properties exactly and, if highly accurate solutions are desired, can be even more efficient than the most popular non-geometric integrators.
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Affiliation(s)
- Seonghoon Choi
- Laboratory of Theoretical Physical Chemistry, Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Jiří Vaníček
- Laboratory of Theoretical Physical Chemistry, Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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10
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Olivucci M, Tran T, Worth GA, Robb MA. Unlocking the Double Bond in Protonated Schiff Bases by Coherent Superposition of S 1 and S 2. J Phys Chem Lett 2021; 12:5639-5643. [PMID: 34110826 DOI: 10.1021/acs.jpclett.1c01379] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The primary event occurring during the E-to-Z photoisomerization reaction of retinal protonated Schiff base (rPSB) is single-to-double bond inversion. In this work we examine the nuclear dynamics that occurs when the initial excited state is a superposition of the S1 and S2 electronic excited states that might be created in a laser experiment. The nuclear dynamics is dominated by double bond inversion that is parallel to the derivative coupling vector of S1 and S2. Thus, the molecule behaves as if it were at a conical intersection even if the states are nondegenerate.
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Affiliation(s)
- Massimo Olivucci
- Chemistry Deparment, University of Siena, Via Aldo Moro n. 2, 53100 Siena, Italy
- Chemistry Department, Bowling Green State University, Overman Hall, Bowling Green, Ohio 43403, United States
| | - Thierry Tran
- Department of Chemistry, University College London, 20 Gordon Street, WC1H 0AJ London, United Kingdom
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College, London SW7 2AZ, United Kingdom
| | - Graham A Worth
- Department of Chemistry, University College London, 20 Gordon Street, WC1H 0AJ London, United Kingdom
| | - Michael A Robb
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College, London SW7 2AZ, United Kingdom
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11
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Tran T, Worth GA, Robb MA. Control of nuclear dynamics in the benzene cation by electronic wavepacket composition. Commun Chem 2021; 4:48. [PMID: 36697520 PMCID: PMC9814899 DOI: 10.1038/s42004-021-00485-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 03/05/2021] [Indexed: 01/28/2023] Open
Abstract
The study of coupled electron-nuclear dynamics driven by coherent superpositions of electronic states is now possible in attosecond science experiments. The objective is to understand the electronic control of chemical reactivity. In this work we report coherent 8-state non-adiabatic electron-nuclear dynamics simulations of the benzene radical cation. The computations were inspired by the extreme ultraviolet (XUV) experimental results in which all 8 electronic states were prepared with significant population. Our objective was to study the nuclear dynamics using various bespoke coherent electronic state superpositions as initial conditions in the Quantum-Ehrenfest method. The original XUV measurements were supported by Multi-configuration time-dependent Hartree (MCTDH) simulations, which suggested a model of successive passage through conical intersections. The present computations support a complementary model where non-adiabatic events are seen far from a conical intersection and are controlled by electron dynamics involving non-adjacent adiabatic states. It proves to be possible to identify two superpositions that can be linked with two possible fragmentation paths.
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Affiliation(s)
- Thierry Tran
- Department of Chemistry, University College London, London, UK. .,Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, UK.
| | - Graham A Worth
- Department of Chemistry, University College London, London, UK.
| | - Michael A Robb
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, UK.
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12
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Chang BY, Shin S, Malinovsky VS, Sola IR. Grid-Based Ehrenfest Model To Study Electron-Nuclear Processes. J Phys Chem A 2019; 123:7171-7176. [PMID: 31314529 DOI: 10.1021/acs.jpca.9b05214] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The two-dimensional electron-nuclear Schrödinger equation using soft-core Coulomb potentials has been a cornerstone for modeling and predicting the behavior of one-active-electron diatomic molecules, particularly for processes where both bound and continuum states are important. The model, however, is computationally expensive to extend to more electron or nuclear coordinates. Here we propose use of the Ehrenfest approach to treat the nuclear motion, while the electronic motion is still solved by quantum propagation on a grid. In this work, we present results for a one-dimensional treatment of H2+, where the quantum and semiclassical dynamics can be directly compared, showing remarkably good agreement for a variety of situations. The advantage of the Ehrenfest approach is that it can be easily extended to treat as many nuclear degrees of freedom as needed.
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Affiliation(s)
- Bo Y Chang
- School of Chemistry , Seoul National University , Seoul 08826 , Republic of Korea
| | - Seokmin Shin
- School of Chemistry , Seoul National University , Seoul 08826 , Republic of Korea
| | | | - Ignacio R Sola
- Departamento de Química Física , Universidad Complutense , 28040 Madrid , Spain
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13
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Fedorov DA, Levine BG. Nonadiabatic Quantum Molecular Dynamics in Dense Manifolds of Electronic States. J Phys Chem Lett 2019; 10:4542-4548. [PMID: 31342748 DOI: 10.1021/acs.jpclett.9b01902] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Most nonadiabatic molecular dynamics methods require the determination of a basis of adiabatic or diabatic electronic states at every time step, but in dense manifolds of electronic states, such approaches become intractable. A notable exception is Ehrenfest molecular dynamics, which can be implemented without explicit determination of such a basis but suffers from unphysical behavior when propagation on a mean-field potential energy surface (PES) does not accurately reflect the true dynamics on multiple electronic states. Here we introduce the multiple cloning for dense manifolds of states (MCDMS) method, a systematically improvable approximation to the multiple cloning method. MCDMS avoids both the mean-field PES problem and the need to compute the full electronic spectrum. This is achieved by reformulating multiple cloning to use a subspace of approximate eigenstates constructed from the time-dependent Ehrenfest electronic wave function. By application to model systems, we show that this approach allows a substantial reduction in the size of the required electronic basis without significant loss in accuracy.
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Affiliation(s)
- Dmitry A Fedorov
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Benjamin G Levine
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
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14
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Arasaki Y, Takatsuka K. Chemical bonding and nonadiabatic electron wavepacket dynamics in densely quasi-degenerate excited electronic state manifold of boron clusters. J Chem Phys 2019; 150:114101. [DOI: 10.1063/1.5094149] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Yasuki Arasaki
- Institute for Fundamental Chemistry, Kyoto University, 606-8103 Kyoto, Japan
| | - Kazuo Takatsuka
- Institute for Fundamental Chemistry, Kyoto University, 606-8103 Kyoto, Japan
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15
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Jenkins AJ, Robb MA. The damped Ehrenfest (D-Eh) method: Application to non-adiabatic reaction paths. COMPUT THEOR CHEM 2019. [DOI: 10.1016/j.comptc.2019.02.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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16
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Jenkins AJ, Spinlove KE, Vacher M, Worth GA, Robb MA. The Ehrenfest method with fully quantum nuclear motion (Qu-Eh): Application to charge migration in radical cations. J Chem Phys 2018; 149:094108. [PMID: 30195291 DOI: 10.1063/1.5038428] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An algorithm is described for quantum dynamics where an Ehrenfest potential is combined with fully quantum nuclear motion (Quantum-Ehrenfest, Qu-Eh). The method is related to the single-set variational multi-configuration Gaussian approach (vMCG) but has the advantage that only a single quantum chemistry computation is required at each time step since there is only a single time-dependent potential surface. Also shown is the close relationship to the "exact factorization method." The quantum Ehrenfest method is compared with vMCG for study of electron dynamics in a modified bismethylene-adamantane cation system. Illustrative examples of electron-nuclear dynamics are presented for a distorted allene system and for HCCI+ where one has a degenerate Π system.
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Affiliation(s)
- Andrew J Jenkins
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
| | - K Eryn Spinlove
- Department of Chemistry, University College London, 20, Gordon St., WC1H 0AJ London, United Kingdom
| | - Morgane Vacher
- Department of Chemistry-Ångström, Uppsala University, Lägerhyddsvägen 1, 751 21 Uppsala, Sweden
| | - Graham A Worth
- Department of Chemistry, University College London, 20, Gordon St., WC1H 0AJ London, United Kingdom
| | - Michael A Robb
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
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17
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Polyak I, Jenkins AJ, Vacher M, Bouduban MEF, Bearpark MJ, Robb MA. Charge migration engineered by localisation: electron-nuclear dynamics in polyenes and glycine. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1478136] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
- Iakov Polyak
- Department of Chemistry, Imperial College London, London, UK
- School of Chemistry, Cardiff University, Cardiff, UK
| | - Andrew J. Jenkins
- Department of Chemistry, Imperial College London, London, UK
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | - Morgane Vacher
- Department of Chemistry, Imperial College London, London, UK
- Department of Chemistry-Ångström, The Theoretical Chemistry Programme, Uppsala University, Uppsala, Sweden
| | - Marine E. F. Bouduban
- Department of Chemistry, Imperial College London, London, UK
- Photochemical Dynamics Group, Institute of Chemical Sciences & Engineering and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | | | - Michael A. Robb
- Department of Chemistry, Imperial College London, London, UK
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18
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Crespo-Otero R, Barbatti M. Recent Advances and Perspectives on Nonadiabatic Mixed Quantum–Classical Dynamics. Chem Rev 2018; 118:7026-7068. [DOI: 10.1021/acs.chemrev.7b00577] [Citation(s) in RCA: 301] [Impact Index Per Article: 50.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rachel Crespo-Otero
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom
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19
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Abstract
Ab initio molecular dynamics is an irreplaceable technique for the realistic simulation of complex molecular systems and processes from first principles. This paper proposes a comprehensive and self-contained review of ab initio molecular dynamics from a computational perspective and from first principles. Quantum mechanics is presented from a molecular dynamics perspective. Various approximations and formulations are proposed, including the Ehrenfest, Born–Oppenheimer, and Hartree–Fock molecular dynamics. Subsequently, the Kohn–Sham formulation of molecular dynamics is introduced as well as the afferent concept of density functional. As a result, Car–Parrinello molecular dynamics is discussed, together with its extension to isothermal and isobaric processes. Car–Parrinello molecular dynamics is then reformulated in terms of path integrals. Finally, some implementation issues are analysed, namely, the pseudopotential, the orbital functional basis, and hybrid molecular dynamics.
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20
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Chalabala J, Uhlig F, Slavíček P. Assessment of Real-Time Time-Dependent Density Functional Theory (RT-TDDFT) in Radiation Chemistry: Ionized Water Dimer. J Phys Chem A 2018. [PMID: 29513531 DOI: 10.1021/acs.jpca.8b01259] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ionization in the condensed phase and molecular clusters leads to a complicated chain of processes with coupled electron-nuclear dynamics. It is difficult to describe such dynamics with conventional nonadiabatic molecular dynamics schemes since the number of states swiftly increases as the molecular system grows. It is therefore attractive to use a direct electron and nuclear propagation such as the real-time time-dependent density functional theory (RT-TDDFT). Here we report a RT-TDDFT benchmark study on simulations of singly and doubly ionized states of a water monomer and dimer as a prototype for more complex processes in a condensed phase. We employed the RT-TDDFT based Ehrenfest molecular dynamics with a generalized gradient approximate (GGA) functional and compared it with wave-function-based surface hopping (SH) simulations. We found that the initial dynamics of a singly HOMO ionized water dimer is similar for both the RT-TDDFT/GGA and the SH simulations but leads to completely different reaction channels on a longer time scale. This failure is attributed to the self-interaction error in the GGA functionals and it can be avoided by using hybrid functionals with large fraction of exact exchange (represented here by the BHandHLYP functional). The simulations of doubly ionized states are reasonably described already at the GGA level. This suggests that the RT-TDDFT/GGA method could describe processes following the autoionization processes such as Auger emission, while its applicability to more complex processes such as intermolecular Coulombic decay remains limited.
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Affiliation(s)
- Jan Chalabala
- Department of Physical Chemistry , University of Chemistry and Technology , Technická 5 , 16628 Prague , Czech Republic
| | - Frank Uhlig
- Department of Physical Chemistry , University of Chemistry and Technology , Technická 5 , 16628 Prague , Czech Republic.,Institute for Computational Physics , University of Stuttgart , Allmandring 3 , 70569 Stuttgart , Germany
| | - Petr Slavíček
- Department of Physical Chemistry , University of Chemistry and Technology , Technická 5 , 16628 Prague , Czech Republic.,Jaroslav Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic , Dolejškova 3 , 18200 Prague , Czech Republic
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21
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Ayuso D, Palacios A, Decleva P, Martín F. Ultrafast charge dynamics in glycine induced by attosecond pulses. Phys Chem Chem Phys 2018. [PMID: 28631783 DOI: 10.1039/c7cp01856h] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The combination of attosecond pump-probe techniques with mass spectrometry methods has recently led to the first experimental demonstration of ultrafast charge dynamics in a biomolecule, the amino acid phenylalanine [Calegari et al., Science, 2014, 346, 336]. Using an extension of the static-exchange density functional theory (DFT) method, the observed dynamics was explained as resulting from the coherent superposition of ionic states produced by the broadband attosecond pulse. Here, we have used the static-exchange DFT method to investigate charge migration induced by attosecond pulses in the glycine molecule. We show that the observed dynamics follows patterns similar to those previously found in phenylalanine, namely that charge fluctuations occur all over the molecule and that they can be explained in terms of a few typical frequencies of the system. We have checked the validity of our approach by explicitly comparing with the photoelectron spectra obtained in synchrotron radiation experiments and with the charge dynamics that follows the removal of an electron from a given molecular orbital, for which fully correlated ab initio results are available in the literature. From this comparison, we conclude that our method provides an accurate description of both the coherent superposition of cationic states generated by the attosecond pulse and its subsequent time evolution. Hence, we expect that the static-exchange DFT method should perform equally well for other medium-size and large molecules, for which the use of fully correlated ab initio methods is not possible.
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Affiliation(s)
- David Ayuso
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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22
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Nisoli M, Decleva P, Calegari F, Palacios A, Martín F. Attosecond Electron Dynamics in Molecules. Chem Rev 2017; 117:10760-10825. [DOI: 10.1021/acs.chemrev.6b00453] [Citation(s) in RCA: 261] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Mauro Nisoli
- Department
of Physics, Politecnico di Milano, 20133 Milano, Italy
- Institute for Photonics and Nanotechnologies, IFN-CNR, 20133 Milano, Italy
| | - Piero Decleva
- Dipartimento
di Scienze Chimiche e Farmaceutiche, Universitá di Trieste and IOM- CNR, 34127 Trieste, Italy
| | - Francesca Calegari
- Institute for Photonics and Nanotechnologies, IFN-CNR, 20133 Milano, Italy
- Center for Free-Electron Laser Science, DESY, 22607 Hamburg, Germany
- Department
of Physics, University of Hamburg, 20355 Hamburg, Germany
| | - Alicia Palacios
- Departamento
de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Fernando Martín
- Departamento
de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia, 28049 Madrid, Spain
- Condensed
Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid, Spain
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23
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Vacher M, Bearpark MJ, Robb MA, Malhado JP. Electron Dynamics upon Ionization of Polyatomic Molecules: Coupling to Quantum Nuclear Motion and Decoherence. PHYSICAL REVIEW LETTERS 2017; 118:083001. [PMID: 28282194 DOI: 10.1103/physrevlett.118.083001] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Indexed: 05/23/2023]
Abstract
Knowledge about the electronic motion in molecules is essential for our understanding of chemical reactions and biological processes. The advent of attosecond techniques opens up the possibility to induce electronic motion, observe it in real time, and potentially steer it. A fundamental question remains the factors influencing electronic decoherence and the role played by nuclear motion in this process. Here, we simulate the dynamics upon ionization of the polyatomic molecules paraxylene and modified bismethylene-adamantane, with a quantum mechanical treatment of both electron and nuclear dynamics using the direct dynamics variational multiconfigurational Gaussian method. Our simulations give new important physical insights about the expected decoherence process. We have shown that the decoherence of electron dynamics happens on the time scale of a few femtoseconds, with the interplay of different mechanisms: the dephasing is responsible for the fast decoherence while the nuclear overlap decay may actually help maintain it and is responsible for small revivals.
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Affiliation(s)
- Morgane Vacher
- Department of Chemistry-Ångström, Uppsala University, Uppsala 75120, Sweden and Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Michael J Bearpark
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Michael A Robb
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - João Pedro Malhado
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
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24
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Jenkins AJ, Vacher M, Twidale RM, Bearpark MJ, Robb MA. Charge migration in polycyclic norbornadiene cations: Winning the race against decoherence. J Chem Phys 2016; 145:164103. [DOI: 10.1063/1.4965436] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Andrew J. Jenkins
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Morgane Vacher
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Rebecca M. Twidale
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Michael J. Bearpark
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Michael A. Robb
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
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25
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Abstract
We introduce a theory of chemical bond with a corpuscular picture of electrons. It employs a minimal set of localized electron wave packets with "floating and breathing" degrees of freedom and the spin-coupling of non-orthogonal valence-bond theory. Its accuracy for describing potential energy curves of chemical bonds in ground and excited states of spin singlet and triplet is examined.
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Affiliation(s)
- Koji Ando
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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26
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Jenkins AJ, Vacher M, Bearpark MJ, Robb MA. Nuclear spatial delocalization silences electron density oscillations in 2-phenyl-ethyl-amine (PEA) and 2-phenylethyl-N,N-dimethylamine (PENNA) cations. J Chem Phys 2016; 144:104110. [DOI: 10.1063/1.4943273] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Andrew J. Jenkins
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Morgane Vacher
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Michael J. Bearpark
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Michael A. Robb
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
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27
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Vacher M, Albertani FEA, Jenkins AJ, Polyak I, Bearpark MJ, Robb MA. Electron and nuclear dynamics following ionisation of modified bismethylene-adamantane. Faraday Discuss 2016; 194:95-115. [DOI: 10.1039/c6fd00067c] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have simulated the coupled electron and nuclear dynamics using the Ehrenfest method upon valence ionisation of modified bismethylene-adamantane (BMA) molecules where there is an electron transfer between the two π bonds. We have shown that the nuclear motion significantly affects the electron dynamics after a few fs when the electronic states involved are close in energy. We have also demonstrated how the non-stationary electronic wave packet determines the nuclear motion, more precisely the asymmetric stretching of the two π bonds, illustrating “charge-directed reactivity”. Taking into account the nuclear wave packet width results in the dephasing of electron dynamics with a half-life of 8 fs; this eventually leads to the equal delocalisation of the hole density over the two methylene groups and thus symmetric bond lengths.
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Affiliation(s)
| | | | | | - Iakov Polyak
- Department of Chemistry
- Imperial College London
- UK
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28
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Meisner J, Vacher M, Bearpark MJ, Robb MA. Geometric Rotation of the Nuclear Gradient at a Conical Intersection: Extension to Complex Rotation of Diabatic States. J Chem Theory Comput 2015; 11:3115-22. [PMID: 26575748 DOI: 10.1021/acs.jctc.5b00364] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nonadiabatic dynamics in the vicinity of conical intersections is of essential importance in photochemistry. It is well known that if the branching space is represented in polar coordinates, then for a geometry represented by angle θ, the corresponding adiabatic states are obtained from the diabatic states with the mixing angle θ/2. In an equivalent way, one can study the relation between the real rotation of diabatic states and the resulting nuclear gradient. In this work, we extend the concept to allow a complex rotation of diabatic states to form a nonstationary superposition of electronic states. Our main result is that this leads to an elliptical transformation of the effective potential energy surfaces; i.e., the magnitude of the initial nuclear gradient changes as well as its direction. We fully explore gradient changes that result from varying both θ and ϕ (the complex rotation angle) as a way of electronically controlling nuclear motion, through Ehrenfest dynamics simulations for benzene cation.
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Affiliation(s)
- Jan Meisner
- Computational Chemistry Group, Institute of Theoretical Chemistry, University of Stuttgart , Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Morgane Vacher
- Department of Chemistry, Imperial College London , London SW7 2AZ, United Kingdom
| | - Michael J Bearpark
- Department of Chemistry, Imperial College London , London SW7 2AZ, United Kingdom
| | - Michael A Robb
- Department of Chemistry, Imperial College London , London SW7 2AZ, United Kingdom
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29
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Vacher M, Mendive-Tapia D, Bearpark MJ, Robb MA. Electron dynamics upon ionization: Control of the timescale through chemical substitution and effect of nuclear motion. J Chem Phys 2015; 142:094105. [DOI: 10.1063/1.4913515] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Morgane Vacher
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - David Mendive-Tapia
- Laboratoire CEISAM - UMR CNR 6230, Université de Nantes, 2 Rue de la Houssinière, BP 92208, 44322 Nantes Cedex 3, France
| | - Michael J. Bearpark
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Michael A. Robb
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
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30
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Vacher M, Meisner J, Mendive-Tapia D, Bearpark MJ, Robb MA. Electronic Control of Initial Nuclear Dynamics Adjacent to a Conical Intersection. J Phys Chem A 2014; 119:5165-72. [DOI: 10.1021/jp509774t] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Morgane Vacher
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Jan Meisner
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - David Mendive-Tapia
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Michael J. Bearpark
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Michael A. Robb
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
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