1 Ocak 2020 Dergi makalesi Açık Erişim

Warden, Constance E.; Smith, Daniel G. A.; Burns, Lori A.; Bozkaya, Ugur; Sherrill, C. David

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  <dc:creator>Warden, Constance E.</dc:creator>
  <dc:creator>Smith, Daniel G. A.</dc:creator>
  <dc:creator>Burns, Lori A.</dc:creator>
  <dc:creator>Bozkaya, Ugur</dc:creator>
  <dc:creator>Sherrill, C. David</dc:creator>
  <dc:date>2020-01-01</dc:date>
  <dc:description>The focal-point approach, combining several quantum chemistry computations to estimate a more accurate computation at a lower expense, is effective and commonly used for energies. However, it has not yet been widely adopted for properties such as geometries. Here, we examine several focal-point methods combining MOller-Plesset perturbation theory (MP2 and MP2.5) with coupled-cluster theory through perturbative triples [CCSD(T)] for their effectiveness in geometry optimizations using a new driver for the Psi4 electronic structure program that efficiently automates the computation of composite-energy gradients. The test set consists of 94 closed-shell molecules containing first- and/or second-row elements. The focal-point methods utilized combinations of correlation-consistent basis sets cc-pV(X+d)Z and heavy-aug-cc-pV(X+d)Z (X = D, T, Q, 5, 6). Focal-point geometries were compared to those from conventional CCSD(T) using basis sets up to heavy-aug-cc-pV5Z and to geometries from explicitly correlated CCSD(T)-F12 using the cc-pVXZ-F12 (X = D, T) basis sets. All results were compared to reference geometries reported by Karton et al. [J. Chem. Phys. 145, 104101 (2016)] at the CCSD(T)/heavy-aug-cc-pV6Z level of theory. In general, focal-point methods based on an estimate of the MP2 complete-basis-set limit, with a coupled-cluster correction evaluated in a (heavy-aug-)cc-pVXZ basis, are of superior quality to conventional CCSD(T)/(heavy-aug-)cc-pV(X+1)Z and sometimes approach the errors of CCSD(T)/(heavy-aug-)cc-pV(X+2)Z. However, the focal-point methods are much faster computationally. For the benzene molecule, the gradient of such a focal-point approach requires only 4.5% of the computation time of a conventional CCSD(T)/cc-pVTZ gradient and only 0.4% of the time of a CCSD(T)/cc-pVQZ gradient.</dc:description>
  <dc:identifier>https://aperta.ulakbim.gov.trrecord/5751</dc:identifier>
  <dc:identifier>oai:zenodo.org:5751</dc:identifier>
  <dc:rights>info:eu-repo/semantics/openAccess</dc:rights>
  <dc:rights>http://www.opendefinition.org/licenses/cc-by</dc:rights>
  <dc:source>JOURNAL OF CHEMICAL PHYSICS 152(12)</dc:source>
  <dc:title>Efficient and automated computation of accurate molecular geometries using focal-point approximations to large-basis coupled-cluster theory</dc:title>
  <dc:type>info:eu-repo/semantics/article</dc:type>
  <dc:type>publication-article</dc:type>
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