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Article
Assessment of Perturbative Explicitly Correlated Methods for Prototypes of Multiconfiguration Electronic Structure
Journal of Chemical Theory and Computation
  • Luke Roskop, Iowa State University
  • Liguo Kong, Virginia Polytechnic Institute and State University
  • Edward F. Valeev, Virginia Polytechnic Institute and State University
  • Mark S. Gordon, Iowa State University
  • Theresa Lynn Windus, Iowa State University
Document Type
Article
Disciplines
Publication Version
Published Version
Publication Date
1-1-2014
DOI
10.1021/ct4006773
Abstract

The performance of the [2]S and [2]R12 universal perturbative corrections that account for one- and many-body basis set errors of single- and multiconfiguration electronic structure methods is assessed. A new formulation of the [2]R12 methods is used in which only strongly occupied orbitals are correlated, making the approach more amenable for larger computations. Three model problems are considered using the aug-cc-pVXZ (X = D,T,Q) basis sets: the electron affinity of fluorine atom, a conformational analysis of two Si2H4structures, and a description of the potential energy surfaces of the X 1Σg+, a 3Πu, b 3Σg-, and A1Πu states of C2. In general, the [2]R12 and [2]S corrections enhance energy convergence for conventional multireference configuration interaction (MRCI) and multireference perturbation theory (MRMP2) calculations compared to their complete basis set limits. For the electron affinity of the F atom, [2]R12 electron affinities are within 0.001 eV of the experimental value. The [2]R12 conformer relative energy error for Si2H4 is less than 0.1 kcal/mol compared to the complete basis set limit. The C2 potential energy surfaces show nonparallelity errors that are within 0.7 kcal/mol compared to the complete basis set limit. The perturbative nature of the [2]R12 and [2]S methods facilitates the development of a straightforward text-based data exchange standard that connects an electronic structure code that can produce a two-particle density matrix with a code that computes the corrections. This data exchange standard was used to implement the interface between the GAMESS MRCI and MRMP2 codes and the MPQC [2]R12 and [2]S capabilities.

Comments

Reprinted (adapted) with permission from Journal of Chemical Theory and Computation 10 (2014): 90, doi:10.1021/ct4006773. Copyright 2014 American Chemical Society.

Copyright Owner
American Chemical Society
Language
en
File Format
application/pdf
Citation Information
Luke Roskop, Liguo Kong, Edward F. Valeev, Mark S. Gordon, et al.. "Assessment of Perturbative Explicitly Correlated Methods for Prototypes of Multiconfiguration Electronic Structure" Journal of Chemical Theory and Computation Vol. 10 Iss. 1 (2014) p. 90 - 101
Available at: http://works.bepress.com/theresa-windus/10/