Newcastle University ePrints -eprint.ncl.ac.uk Medcraft C, Bittner DM, Tew DP, Walker NR, Legon AC. Geometries of H2S-MI (M = Cu, Ag, Au) complexes studied by rotational spectroscopy: The effect of the metal atom. This is the peer reviewed version of the following article: Medcraft C, Bittner DM, Tew DP, Walker NR, Legon AC. Geometries of H2S-MI (M = Cu, Ag, Au) complexes studied by rotational spectroscopy: The effect of the metal atom. ABSTRACT Complexes formed between H2S and each of CuI, AgI

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... and AuI have been isolated and structurallycharacterised in the gas phase. The H2SMI complexes (where M is the metal atom) are generated through laser vaporisation of a metal rod in the presence of a low concentration of H2S and CF3I in a buffer gas of argon undergoing supersonic expansion. The microwave spectra of six isotopologues of each of H2SCuI and H2SAgI; and three isotopologues of H2SAuI have been measured by chirped-pulse Fourier transform microwave (CP-FTMW) spectroscopy. The spectra are interpreted to determine geometries for the complexes and to establish the values of structural parameters. The complexes have Cs symmetry at equilibrium and have a pyramidal configuration about the sulfur atom. The local C2 axis of the hydrogen sulfide molecule intersects the linear axis defined by the three heavy atoms at an angle, φ = 75.00(47)• for M=Cu, φ = 78.43(76)• for M=Ag and φ = 71.587(13)• for M=Au. The trend in the molecular geometries is consistent with significant relativistic effects in the gold-containing complex. The force constant describing the interaction between the H2S and MI sub-units is determined from the measured centrifugal distortion constant, J, of each complex. Nuclear quadrupole coupling constants, χaa(M) and χaa(I) (where M denotes the metal atom), are determined for H2SCuI and H2SAuI for the first time.