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Title: General active space commutator-based coupled cluster theory of general excitation rank for electronically excited states: Implementation and application to ScH

We present a new implementation of general excitation rank coupled cluster theory for electronically excited states based on the single-reference multi-reference formalism. The method may include active-space selected and/or general higher excitations by means of the general active space concept. It may employ molecular integrals over the four-component Lévy-Leblond Hamiltonian or the relativistic spin-orbit-free four-component Hamiltonian of Dyall. In an initial application to ground- and excited states of the scandium monohydride molecule we report spectroscopic constants using basis sets of up to quadruple-zeta quality and up to full iterative triple excitations in the cluster operators. Effects due to spin-orbit interaction are evaluated using two-component multi-reference configuration interaction for assessing the accuracy of the coupled cluster results.
Authors:
; ;  [1] ;  [2]
  1. Laboratoire de Chimie et Physique Quantiques, IRSAMC, Université Paul Sabatier Toulouse III, 118 Route de Narbonne, F-31062 Toulouse (France)
  2. Theoretical Chemistry, Langelandsgade 140, Aarhus University, DK-8000 Århus C (Denmark)
Publication Date:
OSTI Identifier:
22251401
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 139; Journal Issue: 19; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACCURACY; COMMUTATORS; CONFIGURATION INTERACTION; EXCITATION; EXCITED STATES; HAMILTONIANS; L-S COUPLING; RELATIVISTIC RANGE; SCANDIUM