FOURIER-TRANSFORM INFRARED SPECTROMETRY STUDIES OF SURFACE AND BULK POROSITY OF WATER ICE

Water ices used as mimics in laboratory studies of heterogeneous chemi cal reactions have been investigated by FTIR. Water ice as vacuum depo sited onto a CsI substrate at 5 K was found to be essentially non-poro us. Inert gas pre-deposition and co-deposition followed by temperature cycling induced surface and bulk porosity into the produced layers. P orosity was monitored by the shape and position of the 3300 cm(-1) cou pled water band, by the dangling OH high frequency mode, and by the mo des of hydrogen bonded and trapped CO. The highest amount of dangling OH bonds was revealed with Ar/H2O deposition mixtures whereas the high est degree of bulk porosity was achieved with neon as co-deposited gas .