The sticking probability of D2O-water on ice: Isotope effects and the inﬂuence of vibrational excitation
The present study measures the sticking probability of heavy water (D2O) on H2O- and on D2O-ice and probes the inﬂuence of selective OD-stretch excitation on D2O 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 D2O on H2 O-ice was found to be 1% lower than on D2O-ice. OD-stretch excitation by IR laser pumping of the incident D2O molecules produces no detectable change of the D2O 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.