Equilibrium Gas-Phase Structures of Sodium Fluoride, Bromide, and Iodide Monomers and Dimers

Derek A. Wann, David W. H. Rankin, Philip D. McCaffrey, Jan M. L. Martin, Richard J. Mawhorter

Research output: Contribution to journalArticlepeer-review

Abstract

The alkali halides sodium fluoride, sodium bromide, and sodium iodide exist in the gas phase as both monomer and dimer species. A reanalysis of gas electron diffraction (GED) data collected earlier has been undertaken for each of these molecules using the EXPRESS method to yield experimental equilibrium structures. EXPRESS allows amplitudes of vibration to be estimated and correction terms to be applied to each pair of atoms in the refinement model. These quantities are calculated from the ab initio potential-energy surfaces corresponding to the vibrational modes of the monomer and dimer. Because they include many of the effects associated with large-amplitude modes of vibration and anharmonicity, we have been able to determine highly accurate experimental structures. These results are found to be in good agreement with those from high-level core-valence ab initio calculations and are substantially more precise than those obtained in previous structural studies.

Original languageEnglish
Pages (from-to)1927-1935
Number of pages9
JournalThe Journal of Physical Chemistry A
Volume118
Issue number10
Early online date19 Feb 2014
DOIs
Publication statusPublished - 13 Mar 2014

Keywords

  • ALKALI-HALIDE DIMERS
  • GAUSSIAN-BASIS SETS
  • CORRELATED MOLECULAR CALCULATIONS
  • AB-INITIO CALCULATIONS
  • VALENCE BASIS-SETS
  • 2ND ROW ATOMS
  • ELECTRON-DIFFRACTION
  • VIBRATIONAL FREQUENCIES
  • CRYSTALLINE PHASES
  • IONIC MODELS

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