Electronically nonadiabatic dynamics methods based on a self-consistent potential, such as semiclassical Ehrenfest and coherent switching with decay of mixing, have a number of advantages but are computationally slower than approximations based on an unaveraged potential because they require evaluation of all components of the nonadiabatic coupling vector. Here we introduce a new approximation to the self-consistent potential that does not have this computational drawback. The new approximation uses time-derivative couplings evaluated by overlap integrals of electronic wave functions to approximate the nonadiabatic coupling terms in the equations of motion. We present a numerical test of the method for ethylene that shows there is little loss of accuracy in the ensemble-averaged results. This new approximation to the self-consistent potential makes direct dynamics calculations with self-consistent potentials more efficient for complex systems and makes them practically affordable for some cases where the cost was previously too high.
Bibliographical noteFunding Information:
This work was supported in part by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award DE-SC0015997, and by the National Natural Science Foundation of China under Grant No. 51536002.
Copyright © 2020 American Chemical Society.
PubMed: MeSH publication types
- Journal Article