Knowledge Bank

Infrared spectra of benzene-(methonal)$\mu$m clusters formed in a jet-cooled molecular beam are recorded in the methanol $\nu 1$ O-H stretch region (3100 to $3800cm-1$). RIDIRS utilizes Resonant, 2-Photon Ionization Time-of-Flight Mass Spectroscopy (R2PI-TOFMS) to monitor a size selected cluster#### 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#### 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 calculation, provide structural information about each cluster. Chain structures exist for benzene-(methanol)$\mathrm{<mrow\; data-mjx-texclass="ORD">1-3</mrow>}$: and methanol cyclic structures are attached to benzene in benzene-(methanol)$\mathrm{<mrow\; data-mjx-texclass="ORD">4-6</mrow>}$.