Linear infrared spectra and laser-induced resonant desorption in the coadsorbate 12C 16O/ 13C 16O - NaCl

Abstract

Infrared spectra of carbon monoxide isotope mixtures adsorbed on NaCl film and NaCl(100) single crystal surfaces are presented, the spectral linewidths being unusually small with (4±0.2) cm −1 and (1.7±0.2) cm −1, respectively. In isotope mixture studies the frequency shifts due to dipole-dipole coupling have been measured to be (3.5±0.2) cm −1 for the film and (4.0±0.2) cm −1 for the single crystal surface. Isosteric heats of adsorption have been measured and found to be significantly smaller than the energy of the fundamental CO stretching vibration. After isotope selective excitation of this vibration, desorption without isotope selectivity is observed. v-v transfer between the isotopes is considered.