Different flavors of exact-factorization-based mixed quantum-classical methods for multistate dynamics

Villaseco Arribas, Evaristo; Vindel-Zandbergen, Patricia; Roy, Saswata; Maitra, Neepa T.

doi:10.1039/d3cp03464j

Cited by 6 publications

(12 citation statements)

References 80 publications

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“…The additional contributions allow one to describe decoherence effects, as it has been extensively discussed in the literature 37,48,64 . Furthermore, the extra term in the electronic evolution equation ( 14) provides a new mechanism for population transfer mediated by the quantum momentum, that has been shown to be key in accurately capturing multi-state processes such as dynamics through a three-state conical intersection 35,53 .…”

Section: Exact Factorization Of the Molecular Wavefunctionmentioning

confidence: 99%

“…Ciccotti and coworkers rigorously reformulated 42,43 the nuclear equation using the method of characteristics, that can be interpreted as quantum trajectories in a Bohmian sense 44 , but the main computational advantage has been achieved with a more classical-like treatment of the nuclear dynamics 33,[45][46][47] . Algorithms such as the coupled-trajectory mixed quantum-classical (CTMQC) scheme 45,[48][49][50] , along with its energyconserving variation CTMQC-E 51 , and coupled-trajectory Tully surface hopping (CTTSH) 47 allowed us to simulate nonadiabatic processes of various molecular models 36,51,52 and molecular systems using an on-the-fly approach 30,38,53 .…”

Section: Introductionmentioning

confidence: 99%

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Exact-factorization study of the photochemistry of phenol

Pollien,

Villaseco Arribas,

Lauvergnat

et al. 2024

Preprint

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We present an analysis of the performance of the coupled-trajectory schemes for nonadiabatic dynamics derived from the exact factorization of the electron-nuclear wavefunction and implemented in the G-CTMQC code. These algorithms can be seen as variations of the standard Ehrenfest method and Tully surface hopping, which are based, however, on independent trajectories. The reported analysis aims to compare the coupled-trajectory and the independent-trajectory schemes, and to benchmark the numerical results against exact quantum waavepacket dynamics. To this end, we employ an analyitical molecular model with two nuclear degrees of freedom and three electronic states that allows us to describe the photo-induced hydrogen dissociation in phenol. The analysis focuses on different electronic and nuclear properties calculated along the nonadiabatic dynamics of phenol.

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Section: Exact Factorization Of the Molecular Wavefunctionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Exact-factorization study of the photochemistry of phenol

Pollien,

Villaseco Arribas,

Lauvergnat

et al. 2024

Preprint

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“…Variations of the CTMQC algorithm have been explored, for example, using the electronic equation (eq ) within a surface-hopping (SH) or Ehrenfest (Eh) scheme for the nuclear evolution, ,− resulting in a family of trajectory-based methods. A central feature of these methods is the coupling of trajectories through the nuclear quantum momentum (eq ) appearing in the EF terms.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Significance of Energy Conservation in Coupled-Trajectory Approaches to Nonadiabatic Dynamics

Arribas,

Ibele,

Lauvergnat

et al. 2023

J. Chem. Theory Comput.

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Through approximating electron−nuclear correlation terms in the exact factorization approach, trajectory-based methods have been derived and successfully applied to the dynamics of a variety of light-induced molecular processes, capturing quantum (de)coherence effects rigorously. These terms account for the coupling among the trajectories, recovering the nonlocal nature of quantum nuclear dynamics that is completely overlooked in traditional independent-trajectory algorithms. Nevertheless, some of the approximations introduced in the derivation of some of these methods do not conserve the total energy. We analyze energy conservation in the coupledtrajectory mixed quantum-classical (CTMQC) algorithm and explore the performance of a modified algorithm, CTMQC-E, where some of the terms are redefined to restore energy conservation. A set of molecular models is used as a test, namely, 2-cis-penta-2,4-dienimium cation, bis(methylene) adamantyl radical cation, butatriene cation, uracil radical cation, and neutral pyrazine.

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“…45 Compared to CTMQC, independent-trajectory mixed quantum-classical (ITMQC) methods based on XF offer notable advantages in terms of computational cost and robustness to failures of individual trajectories. They demonstrate better stability and energy conservation properties, 46 even though there are several methods considering energy conservation at the ensemble level given that imposing the energy conservation at each trajectory is too strict. 47,48,12,42 Instead of collecting information from the swarms of trajectories, the ITMQC method employs auxiliary trajectories (ATs) placed on all of the excited states for each "real" trajectory.…”

Section: Introductionmentioning

confidence: 99%

Nonadiabatic Dynamics with Exact Factorization: Implementation and Assessment

Han,

Akimov

2024

J. Chem. Theory Comput.

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In this work, we report our implementation of several independent-trajectory mixed-quantum-classical (ITMQC) nonadiabatic dynamics methods based on exact factorization (XF) in the Libra package for nonadiabatic and excited-state dynamics. Namely, the exact factorization surface hopping (SHXF), mixed quantum-classical dynamics (MQCXF), and mean-field (MFXF) are introduced. Performance of these methods is compared to that of several traditional surface hopping schemes, such as the fewest-switches surface hopping (FSSH), branching-corrected surface hopping (BCSH), and the simplified decay of mixing (SDM), as well as conventional Ehrenfest (mean-field, MF) method. Based on a comprehensive set of 1D model Hamiltonians, we find the ranking SHXF ≈ MQCXF > BCSH > SDM > FSSH ≫ MF, with the BCSH sometimes outperforming the XF methods in terms of describing coherences. Although the MFXF method can yield reasonable populations and coherences for some cases, it does not conserve the total energy and is therefore not recommended. We also find that the branching correction for auxiliary trajectories is important for the XF methods to yield accurate populations and coherences. However, the branching correction can worsen the quality of the energy conservation in the MQCXF. Finally, we find that using the time-dependent Gaussian width approximation used in the XF methods for computing decoherence correction can improve the quality of energy conservation in the MQCXF dynamics. The parameter-free scheme of Subotnik for computing the Gaussian widths is found to deliver the best performance in situations where such widths are not known a priori.

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Different flavors of exact-factorization-based mixed quantum-classical methods for multistate dynamics

Abstract: The exact factorization approach has led to the development of new mixed quantum-classical methods for simulating coupled electron-ion dynamics. We compare their performance for dynamics when more than two electronic...

Cited by 6 publications

References 80 publications

Exact-factorization study of the photochemistry of phenol

Exact-factorization study of the photochemistry of phenol

Significance of Energy Conservation in Coupled-Trajectory Approaches to Nonadiabatic Dynamics

Nonadiabatic Dynamics with Exact Factorization: Implementation and Assessment

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