ANALYSIS OF VAN-DER-WAALS VIBRATIONS IN SMALL (N=1 TO 4) AROMATIC-(RARE GAS)(N) CLUSTERS

A set of new, or improved, experimental R2P2CI spectra of the various structural isomers of aniline-(argon)(n) clusters with n = 1 to 4 have been obtained in the region of the S-1-S-0 origin band. They exhibit a very large number of sharp VdW excited bands. A simplified mechanical model has been developped to describe the solvent to chromophore motions in the different isomers. From this restricted harmonic description of the force field, force constants and reduced masses were derived from fitting the spectra of the simple (1\0), (1\1),(2\0), (3\0) clusters, which allowed to make predictions for the VdW frequencies of the more complex (2\1) and (3\1) clusters and thus to propose assignments for the experimentally observed bands.