Infrared Characterization of Simple Adducts of Matrix-Isolated Cesium Fluoride and Sodium Chloride with Dihydrogen:  Evidence of a Cation Interaction

H 2 -doped argon matrices containing CsF were examined using FTIR with 1 cm - 1 spectral resolution. Several distinct trapping sites were identified with one, two, and three hydrogen molecules perturbed by CsF. CsF(H 2 ) gives a band at 4022 cm - 1 while the features of CsF(H 2 ) x, x > 1, are displaced to higher wavenumbers. It is clear from the similarity of the spectra of H 2 and HD that the rotation of H 2 is quenched in the presence of CsF. Analogous spectra are observed using KF with the 1:1 adduct absorbing at 4016 cm - 1 . The spectrum of H 2 in argon matrices doped with NaCl shows three absorptions that exhibit fine structure even under highly dilute conditions. Analogous features are exhibited by HD, indicating that the several bands are probably not due to rotation of the hydrogen. The three bands are assigned to conformers of NaCl:H 2 which are differentiated by an interaction between the sodium ion and H 2 that is modulated by the matrix.