Structure and morphology of gas phase deposited ice

Abstract

Abstract Amorphous ice was prepared by deposition of H 2 O vapour diluted in heat exchange gases such as He or Ar at low temperatures (13 to 45 K). This technique is faster than the deposition of pure H 2 O vapour. The rapid sticking of condensing molecules on the cold solid leads to a poor short range order inside the grains. The high nucleation rate during vapour deposition results in small grain sizes and microporosity. Structure and morphology of the resulting amorphous ice samples were characterized by x‐ray diffraction. The radial distribution function was calculated from the diffraction data of pure ice and proved to be consistent with the Continuous Random Network model. Diffraction patterns of krypton layers on the amorphous ice reflect the morphology of the substrate: at the beginning micropores with a diameter of 15–20 Å and a volume of 0.045 cm 3 /g are filled. At higher mass coverages outer grain surfaces and large voids are covered by krypton.