Makhov, DV, Glover, WJ, Martinez, TJ et al. (1 more author) (2014) Ab initio multiple cloning algorithm for quantum nonadiabatic molecular dynamics. Journal of Chemical Physics, 141 (5). 054110. ISSN 0021-9606
Abstract
We present a new algorithm for ab initio quantum nonadiabatic molecular dynamics that combines the best features of ab initio Multiple Spawning (AIMS) and Multiconfigurational Ehrenfest (MCE) methods. In this new method, ab initio multiple cloning (AIMC), the individual trajectory basis functions (TBFs) follow Ehrenfest equations of motion (as in MCE). However, the basis set is expanded (as in AIMS) when these TBFs become sufficiently mixed, preventing prolonged evolution on an averaged potential energy surface. We refer to the expansion of the basis set as "cloning," in analogy to the "spawning" procedure in AIMS. This synthesis of AIMS and MCE allows us to leverage the benefits of mean-field evolution during periods of strong nonadiabatic coupling while simultaneously avoiding mean-field artifacts in Ehrenfest dynamics. We explore the use of time-displaced basis sets, "trains," as a means of expanding the basis set for little cost. We also introduce a new bra-ket averaged Taylor expansion (BAT) to approximate the necessary potential energy and nonadiabatic coupling matrix elements. The BAT approximation avoids the necessity of computing electronic structure information at intermediate points between TBFs, as is usually done in saddle-point approximations used in AIMS. The efficiency of AIMC is demonstrated on the nonradiative decay of the first excited state of ethylene. The AIMC method has been implemented within the AIMS-MOLPRO package, which was extended to include Ehrenfest basis functions.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | Copyright 2014 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Makhov DV, Glover WJ, Martinez TJ, Shalashilin DV (2014) Journal of Chemical Physics 141, 054110 and may be found at http://dx.doi.org/10.1063/1.4891530 |
Keywords: | Algorithms; Computer Simulation; Energy Transfer; Models, Chemical; Molecular Dynamics Simulation; Phase Transition; Quantum Theory; Software; Thermodynamics |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemistry (Leeds) > Physical Chemistry (Leeds) The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 09 Oct 2015 14:24 |
Last Modified: | 20 Jun 2021 08:37 |
Published Version: | http://dx.doi.org/10.1063/1.4891530 |
Status: | Published |
Publisher: | American Institute of Physics |
Identification Number: | 10.1063/1.4891530 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:88795 |