Non-covalent Interaction of Benzene with Methanol and Diethyl Ether Solid Surfaces

We present laboratory experiments on binary, layered ices comprised of benzene (C₆H₆) on methanol (CH₃OH) and on diethyl ether (CH₃CH₂OCH₂CH₃). Temperature programmed desorption (TPD) and reflection-absorption infrared spectroscopy (RAIRS) have been used to elucidate the growth mechanisms in these systems. Ab initio quantum chemical calculations on simple gas-phase model clusters are used to aid interpretation of the experimental data by highlighting the key interactions established at the interface. Our observations are consistent with C₆H₆ forming islands on CH₃OH, although evidence of strong hydrogen bonding interactions indicates some degree of surface wetting. In contrast, layer-by-layer growth is proposed for C₆H₆ on the CH₃CH₂OCH₂CH₃ substrate.