Analytical Derivative Coupling for Multistate CASPT2 Theory

The probability of nonradiative transitions in photochemical dynamics is determined by the derivative couplings, the couplings between different electronic states through the nuclear degrees of freedom. Efficient and accurate evaluation of the derivative couplings is, therefore, of central importanc...

Full description

Saved in:
Bibliographic Details
Published in:Journal of chemical theory and computation 2017-06, Vol.13 (6), p.2561-2570
Main Authors: Park, Jae Woo, Shiozaki, Toru
Format: Article
Language:English
Subjects:
Algorithms
Computer simulation
Configuration interaction
Cost analysis
Coupling (molecular)
Couplings
Electron states
Energy gradient
Ethylenes - chemistry
Fluorescence
Intersections
Mathematical models
Models, Molecular
Molecular chains
Molecular Conformation
Nuclear energy
Nuclear engineering
Nuclear reactions
Nuclear reactors
Perturbation theory
Photochemical reactions
Proteins
Quantum Theory
Stilbene
Thermodynamics
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The probability of nonradiative transitions in photochemical dynamics is determined by the derivative couplings, the couplings between different electronic states through the nuclear degrees of freedom. Efficient and accurate evaluation of the derivative couplings is, therefore, of central importance to realize reliable computer simulations of photochemical reactions. In this work, the derivative couplings for multistate multireference second-order perturbation theory (MS-CASPT2) and its “extended” variant (XMS-CASPT2) are studied, in which we present an algorithm for their analytical evaluation. The computational costs for evaluating the derivative couplings are essentially the same as those for calculating the nuclear energy gradients. The geometries and energies calculated with XMS-CASPT2 for small molecules at minimum energy conical intersections (MECIs) are in good agreement with those computed by multireference configuration interaction. As numerical examples, MECIs are optimized using XMS-CASPT2 for stilbene and a green fluorescent protein model chromophore (the 4-para-hydroxybenzylidene-1,2-dimethyl-imidazolin-5-one anion).
ISSN:1549-9618
1549-9626
DOI:10.1021/acs.jctc.7b00018