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130th General Meeting of Korean Chemical Society Nonadiabatic dynamics simulations using low-cost multireference perturbation theories (XMS-CASPT2D and SA-DSRG-MRPT2)

Submission Date :
8 / 5 / 2022 , 15 : 43 : 46
Abstract Number :
Presenting Type:
Poster Presentation
Presenting Area :
Physical Chemistry
Authors :
WooJoo Han, Jae Woo Park1,*
department of chemistry, Chungbuk National University, Korea
1Department of Chemistry, Chungbuk National University, Korea
Assigned Code :
Presenting Time :
Direct dynamics simulations, in which ab initio quantum chemistry calculations are used to compute potential energy surfaces in the molecular dynamics (MD) simulations, are probably one of the most accurate approaches for studying the mechanisms of photochemical processes. As multireference quantum chemistry methods treat the ground and excited states on an equal footing, they are suitable for describing nonadiabatic processes. However, the applicability of such simulations has been limited due to their overwhelming computational cost. Here, we benchmarked low-cost multireference perturbation theories (MRPTs) for performing Tully’s fewest switches surface hopping (FSSH) dynamics simulations for the retinal model chromophore molecule penta-2,4-dieniminium cation (PSB3) in vacuo and in solution phase. In particular, we have tested diagonal extended multistate complete active space second-order perturbation theory (XMS-CASPT2D) and state-averaged second-order multireference-driven similarity renormalization group perturbation theory (SA-DSRG-MRPT2). The computational demands for these methods are moderate and are suitable for performing nonadiabatic simulations in a small computer cluster, such that we performed the simulation of 100 and 200 trajectories in solution and gas phases, respectively. We also compared the simulation results obtained by these two ab initio methods.