Adsorption of small molecules on amorphous ice: volumetric and FT-IR isotherm co-measurements: Part I. Different probe molecules

Ar, Kr, CH4, N2, CO and CF4 adsorption on amorphous ice has been studied by using a combination of volumetric isotherm measurements and FT-IR spectroscopy. We have been able to characterize the modifications in the three vibrational surface modes of ice throughout the adlayer formation and to observe different types of wetting. For these gases, we have measured the net heat of adsorption within a range of 1–2.6 kJ mol−1, showing the weakness of surface interaction and conversely, we have measured the shift of the dangling OH bond within a range of 7–60 cm−1, showing its high sensitivity to the adsorption process. We have succeeded in correlating both techniques by measuring the evolution of vibrational surface modes as a function of the relative pressure, from submonolayer to bulk.