A hybrid memory kernel approach for condensed phase non-adiabatic dynamics
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1704.07477.pdf
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1.34 MB
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Author(s)
Hait, Diptarka
Mavros, Michael George
Van Voorhis, Troy
Date Issued
July 2017
Journal
The Journal of Chemical Physics
Publisher
American Institute of Physics (AIP)
Citation
Hait, Diptarka et al. “A Hybrid Memory Kernel Approach for Condensed Phase Non-Adiabatic Dynamics.” The Journal of Chemical Physics 147, 1 (July 2017): 014108 © 2017 Author(s)
Version
Author's final manuscript
Abstract
The spin-boson model is a simplified Hamiltonian often used to study non-adiabatic dynamics in large condensed phase systems, even though it has not been solved in a fully analytic fashion. Herein, we present an exact analytic expression for the dynamics of the spin-boson model in the infinitely slow-bath limit and generalize it to approximate dynamics for faster baths. We achieve the latter by developing a hybrid approach that combines the exact slow-bath result with the popular non-interacting blip approximation (NIBA) method to generate a memory kernel that is formally exact to second-order in the diabatic coupling but also contains higher-order contributions approximated from the second-order term alone. This kernel has the same computational complexity as the NIBA, but is found to yield dramatically superior dynamics in regimes where the NIBA breaks down - such as systems with large diabatic coupling or energy bias. This indicates that this hybrid approach could be used to cheaply incorporate higher-order effects into second-order methods and could potentially be generalized to develop alternate kernel resummation schemes.
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
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Creative Commons Attribution-Noncommercial-Share Alike
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DOI of Published Version
https://doi.org/10.1063/1.4990739
