Accurate computational thermochemistry from explicitly correlated coupled-cluster theory

Wim Klopper*, Rafal A. Bachorz, Christof Haettig, David P. Tew

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

51 Citations (Scopus)

Abstract

Explicitly correlated coupled-cluster theory has developed into a valuable computational tool for the calculation of electronic energies close to the limit of a complete basis set of atomic orbitals. In particular at the level of coupled-cluster theory with single and double excitations (CCSD), the space of double excitations is quickly extended towards a complete basis when Slater-type geminals are added to the wave function expansion. The purpose of the present article is to demonstrate the accuracy and efficiency that can be obtained in computational thermochemistry by a CCSD model that uses such Slater-type geminals. This model is denoted as CCSD(F12), where the acronym F12 highlights the fact that the Slater-type geminals are functions f(r (12)) of the interelectronic distances r (12) in the system. The performance of explicitly correlated CCSD(F12) coupled-cluster theory is demonstrated by computing the atomization energies of 73 molecules (containing H, C, N, O, and F) with an estimated root-mean-square deviation from the values compiled in the Active Thermochemical Tables of sigma = 0.10 kJ/mol per valence electron. To reach this accuracy, not only the frozen-core CCSD basis-set limit but also high-order excitations (connected triple and quadruple excitations), core-valence correlation effects, anharmonic vibrational zero-point energies, and scalar and spin-orbit relativistic effects must be taken into account.

Original languageEnglish
Pages (from-to)289-304
Number of pages16
JournalTheoretical Chemistry Accounts
Volume126
Issue number5-6
DOIs
Publication statusPublished - Aug 2010

Keywords

  • Thermochemistry
  • Atomization energy
  • Coupled-cluster theory
  • Explicitly correlated theory
  • Basis-set extrapolation
  • COMPLETE BASIS-SET
  • GAUSSIAN-BASIS SETS
  • MOLECULAR ELECTRONIC-STRUCTURE
  • CONSISTENT COMPOSITE APPROACH
  • AB-INITIO THERMOCHEMISTRY
  • PERTURBATION-THEORY CALCULATIONS
  • MULTI-COEFFICIENT CORRELATION
  • DENSITY-FUNCTIONAL METHODS
  • AUXILIARY BASIS-SETS
  • INFINITE BASIS-SET

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