VIBRATIONAL FREQUENCY-SHIFTS OF DIATOMIC-MOLECULES IN INTERACTION WITH A NA+ CATION BY AB-INITIO CALCULATIONS - COMPARISON WITH EXPERIMENT ON H-2 AND N-2 ADSORBED IN NAA ZEOLITE

Ab initio calculations on H-2 and N-2 and on the same molecules in the presence of a Na+ cation are presented. The equilibrium configuration and the vibrational frequency shift due to the interaction are calculated. The potential energy surfaces are obtained by local osculatory interpolations and extrapolations. The vibrational frequencies are calculated by the Numerov-Cooley method. The direction of the frequency shift is found to be related to the orientation of the diatomic molecule with respect to the cation. The results are compared with experimental data on induced infrared bands of H-2 and N-2 adsorbed in NaA zeolite.