Quasi-ice monolayer on atomically smooth amorphous SiO2 at room temperature observed with a high-finesse optical resonator -: art. no. 166104

The structure of an H2O monolayer bound to atomically smooth hydroxylated amorphous silica is probed under ambient conditions by near-infrared evanescent-wave cavity ring-down absorption spectroscopy. Employing a miniature monolithic optical resonator, we find sharp (approximate to 10 cm(-1)) and polarized (> 101) vibration-combination bands for surface OH and adsorbed H2O, which reveal ordered species in distinct local environments. Indicating first-monolayer uniqueness, the absorption bands for adsorbed H2O show intensity saturation and line narrowing with completion of one monolayer. Formation of the ordered H2O monolayer likely arises from H bonding to a quasicrystalline surface OH network.