Trends in alkali metal hydrosulfides: A combined Fourier transform microwave/millimeter-wave spectroscopic study of KSH (X1A′)

M. P. Bucchino, P. M. Sheridan, J. P. Young, M. K.L. Binns, D. W. Ewing, L. M. Ziurys

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

The pure rotational spectrum of KSH (X1A′) has been measured using millimeter-wave direct absorption and Fourier transform microwave (FTMW) techniques. This work is the first gas-phase experimental study of this molecule and includes spectroscopy of KSD as well. In the millimeter-wave system, KSH was synthesized in a DC discharge from a mixture of potassium vapor, H2S, and argon; a discharge-assisted laser ablation source, coupled with a supersonic jet expansion, was used to create the species in the FTMW instrument. Five and three rotational transitions in the range 3-57 GHz were recorded with the FTMW experiment for KSH and KSD, respectively, in the K a = 0 component; in these data, potassium quadrupole hyperfine structure was observed. Five to six transitions with Ka = 0-5 were measured in the mm-wave region (260-300 GHz) for the two species. The presence of multiple asymmetry components in the mm-wave spectra indicates that KSH has a bent geometry, in analogy to other alkali hydrosulfides. The data were analyzed with an S-reduced asymmetric top Hamiltonian, and rotational, centrifugal distortion, and potassium electric quadrupole coupling constants were determined for both isotopolgues. The r0 geometry for KSH was calculated to be rS-H = 1.357(1) Å, rK-S = 2.806(1) Å, and θM-S-H (°) = 95.0 (1). FTMW measurements were also carried out on LiSH and NaSH; metal electric quadrupole coupling constants were determined for comparison with KSH. In addition, ab initio computations of the structures and vibrational frequencies at the CCSD(T)/6-311++G(3df,2pd) and CCSD(T)/aug-cc-pVTZ levels of theory were performed for LiSH, NaSH, and KSH. Overall, experimental and computational data suggest that the metal-ligand bonding in KSH is a combination of electrostatic and covalent forces.

Original languageEnglish (US)
Article number214307
JournalJournal of Chemical Physics
Volume139
Issue number21
DOIs
StatePublished - Dec 7 2013

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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