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Title: Model space diabatization for quantum photochemistry

Diabatization is a procedure that transforms multiple adiabatic electronic states to a new representation in which the potential energy surfaces and the couplings between states due to the electronic Hamiltonian operator are smooth, and the couplings due to nuclear momentum are negligible. In this work, we propose a simple and general diabatization strategy, called model space diabatization, that is applicable to multi-configuration quasidegenerate perturbation theory (MC-QDPT) or its extended version (XMC-QDPT). An advantage over previous diabatization schemes is that dynamical correlation calculations are based on standard post-multi-configurational self-consistent field (MCSCF) multi-state methods even though the diabatization is based on state-averaged MCSCF results. The strategy is illustrated here by applications to LiH, LiF, and thioanisole, with the fourfold-way diabatization and XMC-QDPT, and the results illustrate its validity.
Authors:
;  [1] ; ;  [2]
  1. Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455 (United States)
  2. Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States)
Publication Date:
OSTI Identifier:
22416093
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 6; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANISOLE; CORRELATIONS; COUPLING; HAMILTONIANS; LITHIUM FLUORIDES; LITHIUM HYDRIDES; ORGANIC SULFUR COMPOUNDS; PERTURBATION THEORY; PHOTOCHEMISTRY; POTENTIAL ENERGY; SELF-CONSISTENT FIELD; STANDARDS; SURFACES