title: The sticking probability of D2O-water on ice: isotope effects and the influence of vibrational excitation.
abstract: The present study measures the sticking probability of heavy water (D(2)O) on H(2)O- and on D(2)O-ice and probes the influence of selective OD-stretch excitation on D(2)O sticking on these ices. Molecular beam techniques are combined with infrared laser excitation to allow for precise control of incident angle, translational energy, and vibrational state of the incident molecules. For a translational energy of 69 kJ/mol and large incident angles (θ ≥ 45°), the sticking probability of D(2)O on H(2)O-ice was found to be 1% lower than on D(2)O-ice. OD-stretch excitation by IR laser pumping of the incident D(2)O molecules produces no detectable change of the D(2)O sticking probability (<10(-3)). The results are compared with other gas/surface systems for which the effect of vibrational excitation on trapping has been probed experimentally.
authors.affiliation: Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
authors.forename: P Morten
authors.initials: PM
authors.lastname: Hundt
authors.forename: Régis
authors.initials: R
authors.lastname: Bisson
authors.forename: Rainer D
authors.initials: RD
authors.lastname: Beck