Isotope effect in dihydrogen-bonded systems: Application of the analytical energy gradient method in the nuclear orbital plus molecular orbital theory

Hiromi Nakai, Yasuhiro Ikabata, Yasuhiro Tsukamoto, Yutaka Imamura, Kaito Miyamoto, Minoru Hoshino

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

We investigate isotope effects in dihydrogen systems using the nuclear orbital plus molecular orbital (NOMO) theory, which simultaneously determines nuclear and electronic wave functions without the Born-Oppenheimer approximation. In order to estimate the vibrational averaging bond distances, the analytical energy gradients are used for the NOMO theory. The bond distances of three dihydrogen-bonded systems, namely H3NX+ XBeH, LiX XC2H and H2BX XF for X = H, D and T, are obtained. The X X bond distances decrease with respect to the substitution T D H, which is contrary to the behaviour of typical hydrogen bonds. This indicates that isotope effects strengthen the X X bond. This behaviour is analogous to the Ubbelohde effect observed in the solid phase.

Original languageEnglish
Pages (from-to)2649-2657
Number of pages9
JournalMolecular Physics
Volume105
Issue number19-22
DOIs
Publication statusPublished - 2007 Oct 21

    Fingerprint

Keywords

  • Analytical energy gradient
  • Dihydrogen-bonded system
  • Isotope effect
  • Nuclear orbital plus molecular orbital theory
  • Vibrational averaging shift

ASJC Scopus subject areas

  • Biophysics
  • Molecular Biology
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

Cite this