The stretching mode of deposited CO as a probe for the morphology of 5 K ices

The band structure and spectral parameters (peak frequency, bandwidth) of the stretching mode of CO deposited at 5 K upon various ice layers are indicative of CO⋯H2O complexations and thereby of the nature of the ice surface. It is shown that for the former, a strained surface is sufficient and the ice does not have to possess uncoupled OH bonds. The order of crystallinity found is: pure ice deposited on CsI window > pure water deposited on argon and neon layers > neon/H2O solid mixture after neon release > argon/H2O solid mixture after argon release.