TG01		15min1:30

R. N. PRIBBLE, F. C. HAGEMEISTER, C. J. GRUENLOH AND T. S. ZWIER, Department of Chemistry, Purdue University, West Lafayette, IN 47907-1393.

Infrared spectra of benzene-(methanol)_m clusters formed in a jet-cooled molecular beam are recorded in the methanol ₁ O-H stretch region (3100 to 3800 cm^-1). RIDIRS utilizes Resonant 2-Photon Ionization Time-of-Flight Mass Spectroscopy (R2PI-TOFMS) to monitor a size selected cluster's ion signal which is proportional to its neutral ground state population. The tunable infrared output of a Nd:YAG-pumped OPO system is spatially overlapped with the R2PI near-UV pulsed laser beam and precedes it by 80 ns. When in resonance with an infrared transition, population is removed from the cluster's neutral ground state prior to ionization, producing a dip in the R2PI ion signal. Experimental hydrogen-bond vibrational signatures (i.e. vibrational frequency shifts and changes in band widths), along with ab initio calculations, provide structural information about each cluster. Chain structures exist for benzene-(methanol)_1-3, and methanol cyclic structures are attached to benzene in benzene-(methanol)_4-6.