Neutral rare-gas containing charge-transfer molecules in solid matrices. I. HXeCl, HXeBr, HXeI, and HKrCl in Kr and Xe

Abstract

Ultraviolet-irradiation of hydrogen halide containing rare gas matrices yields the formation of linear centrosymmetric cations of type ͑XHX͒ ϩ , ͑XϭAr, Kr, Xe͒. Annealing of the irradiated doped solids produces, along with thermoluminescence, extremely strong absorptions in the 1700-1000 cm Ϫ1 region. Based on isotopic substitution and halogen dependence of these bands, the presence of hydrogen and halogen atom͑s͒ in these species is evident. In the present paper we show the participation of rare gas atom͑s͒ in these new compounds. The evidence is based on studies of the thermally generated species in mixed rare gas matrices. The new species are assigned as neutral charge-transfer molecules HX ϩ Y Ϫ ͑Yϭhalogen͒, and their vibrational spectra are discussed and compared with those calculated with ab initio methods. This is the first time hydrogen and a rare gas atom has been found to make a chemical bond in a neutral stable compound. The highest level ab initio calculations on the existence of compounds of type HXY corroborate the experimental observations. The mechanism responsible for the formation of these species is also discussed.

Matrix effect on vibrational frequencies: Experiments and simulations for HCl and HNgCl (Ng = Kr and Xe)

“…The ratio of the H−Xe and D−Xe stretching frequencies (1.374) is very similar to that measured in a Xe matrix (1.376). 14 In fact, the observed small difference in the H/D frequency ratios is remarkable because it features a decrease of anharmonicity of the H−Xe stretching vibration in a Xe matrix, i.e., the strengthening of chemical bonding of HXeCl upon solvation in a Xe matrix.…”

Destabilization of noble-gas hydrides by a water environment: calculations for HXeOH@(H2O)n, HXeOXeH@(H2O)n, HXeBr@(H2O)n, HXeCCH@(H2O)n

“…The instability of HNgY in water is demonstrated for four experimentally known compounds: HXeBr, 1 HXeCCH, [17][18][19] HXeOH 20 and HXeOXeH. 21 A detailed analysis for the destabilization mechanism and comparison to experimental results are given for the water based HXeOH and HXeOXeH molecules.…”

The radiation-induced chemistry in solid xenon matrices

“…Nevertheless, from the point of view of low-temperature chemistry, solid xenon is a promising host, because it offers much wider range of temperature stability in comparison with other noble gas matrices. Particular interest to this field in the past fifteen years is associated with discovery of a novel family of unusual molecules, noble gas hydrides HNgY (Ng represents a noble gas atom and Y is an electronegative atom or fragment) [26]. This family now includes more than twenty molecules and the majority of them are xenon compounds [27].…”