Infrared Identification of Proton-Bound Rare-Gas Dimers (XeHXe)+, (KrHKr)+, and (KrHXe)+ and Their Deuterated Species in Solid Hydrogen

Proton-bound rare-gas dimer (RgHRg)+, in which Rg represents a rare-gas atom, serves as a prototypical system for proton solvation by inert-gas atoms. Until now, only centrosymmetric species with Rg = Ar, Kr, or Xe have been identified with infrared spectra. We employed electron bombardment during deposition of a mixture of Xe (or Kr) in p-H2 at 3.2 K to prepare (RgHRg)+. Lines at 847.0 and 972.1 cm–1 are assigned as the Rg–H–Rg antisymmetric stretching (ν3) mode and its combination with the Rg–H–Rg symmetric stretching (ν1 + ν3) mode of (XeHXe)+ in solid p-H2, respectively. Lines at 871.1 and 974.0 cm–1 are assigned as the ν3 and ν1 + ν3 modes of (KrHKr)+ in solid p-H2, respectively. Slightly shifted and broadened lines were observed for these species in solid n-H2. These results agree satisfactorily with reported experimental values of (XeHXe)+ and (KrHKr)+ in solid Xe, Kr, and Ar, and with the quantum-chemically predicted anharmonic vibrational wavenumbers of these species in the gaseous phase; the sig...