D2O 水在冰上的附着概率：同位素效应和振动激发的影响。

The sticking probability of D2O-water on ice: isotope effects and the influence of vibrational excitation.

机构信息

Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.

出版信息

J Chem Phys. 2012 Aug 21;137(7):074701. doi: 10.1063/1.4742914.

PMID:22920131

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.

摘要

本研究测量了重水（D(2)O）在 H(2)O- 和 D(2)O-冰上的附着概率，并探测了选择性 OD 伸缩激发对这些冰上 D(2)O 附着的影响。分子束技术与红外激光激发相结合，可精确控制入射角度、入射分子的平动能量和振动状态。对于平动能量为 69 kJ/mol 和较大的入射角（θ≥45°），发现 D(2)O 在 H(2)O-冰上的附着概率比在 D(2)O-冰上低 1%。通过 IR 激光泵浦入射 D(2)O 分子的 OD 伸缩激发，对 D(2)O 附着概率没有可检测到的变化（<10(-3)）。结果与其他气体/表面体系进行了比较，这些体系已经通过实验探测了振动激发对俘获的影响。