Implications of the complete basis set limit in valence bond theory: a case study of molecular hydrogen

Brian J. Duke, Remco W. A. Havenith*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

3 Citations (Scopus)
181 Downloads (Pure)

Abstract

The use of larger basis sets to approach the complete basis limit, now common in quantum chemistry, is applied for the first time to a range of valence bond functions for the simplest case of molecular hydrogen. Good convergence of the energy is slow due to difficulty in getting a correct cusp near the nuclei, but it is significant. The form of the orbitals converges much faster, leading to a slight distortion of the valence bond orbitals and an enhanced overlap, irrespective whether the basis set is restricted to basis functions centred on one atom for each valence bond orbital or the full use of the basis set is allowed. This blurs the distinction between these two approaches and shows that basis set restrictions are not tenable in the complete basis set limit. Furthermore, it supports the general use of the full basis as advocated in the spin-coupled and generalised valence bond methods.

Original languageEnglish
Article number82
Pages (from-to)1-13
Number of pages13
JournalTheoretical Chemistry Accounts
Volume135
Issue number3
DOIs
Publication statusPublished - 5-Mar-2016

Keywords

  • Valence bond theory
  • Complete basis set limit
  • Hydrogen molecule
  • Breathing orbitals
  • Strictly localised orbitals
  • Overlap enhanced (delocal) orbitals
  • 3RD-ORDER OPTICAL NONLINEARITY
  • WALL CARBON NANOTUBES
  • SINGLE-WALL
  • AB-INITIO
  • STATIC POLARIZABILITIES
  • SYSTEMS
  • POLARIZATION
  • EXCHANGE

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