INTERMOLECULAR INTERACTION IN PROTON-BOUND DIMERS - INFRARED PHOTODISSOCIATION SPECTRA OF RG-HOCO+ (RG = HE, NE, AR) COMPLEXES

Infrared photodissociation spectra of the proton-bound Rg-HOCO+ ionic complexes (Rg = He/Ne/Ar) have been recorded in the vicinity of the nu (1) (OH stretch) vibration. The observed complexation-induced red shif ts (Delta nu(1)) are 47, 120, and 704 cm(-1) for the He, Ne and Ar con taining species and correlate linearly with the proton affinity of the rare-gas atom. Weak transitions in the 100-220 cm(-1) range to the bl ue of the nu(1) fundamentals are assigned to combination bands of v, w ith the intermolecular stretching mode, nu(s). The geometries, vibrati onal frequencies and interaction energies of the Rg-HOCO+ complexes ha ve been investigated by ab initio calculations at the MP2 level, and t he results are in good agreement with the experimental data. (C) 1998 Elsevier Science B.V. All rights reserved.