Spectroscopy of acetonitrile (benzene)n clusters, n=1–3. Comparison with benzene clusters

Well-resolved spectra of the small benzene clusters containing a single acetonitrile molecule (BnA) with n=1–3 have been obtained by the (one-color) resonant two-photon ionization technique using benzeneʹs B2u←A1g 601 spectral resonance, and compared with the spectra of neat benzene clusters. While only a single spectral feature is found for the benzene-acetonitrile (BA) complex, three distinct isomers are suggested for the B2A cluster, and two isomers for the B3A cluster. The R2PI spectra obtained, in conjunction with Monte-Carlo (MC) simulations and simple energetic arguments, provide a reasonably compelling picture of the dipole-containing nonpolar molecular cluster system.