Gabriel O, Schram D C, Engeln R
Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
Phys Rev E Stat Nonlin Soft Matter Phys. 2008 Jul;78(1 Pt 2):016407. doi: 10.1103/PhysRevE.78.016407. Epub 2008 Jul 29.
We report on the interaction of hydrogen atoms and molecules under high flux conditions with a cooled copper surface and its impact on gas phase densities and internal excitation of the molecules. These densities were measured by means of laser-induced fluorescence using tunable radiation sources in the vacuum-ultraviolet (vuv). While H atoms were detected by two-photon absorption laser-induced fluorescence, the necessary vuv radiation for the detection of rovibrationally excited H2 molecules in the electronic ground state were produced by stimulated anti-Stokes Raman scattering. The results reveal a strong loss mechanism of H atoms and the formation of rovibrationally excited H2 molecules due to surface interaction. The surface reaction probability of H atoms under high flux conditions on copper was estimated. Surface collisions are shown to have a profound influence on the density distribution of rovibrationally excited H2 molecules: The distributions follow lower temperatures and are less Boltzmann-like, i.e., the distributions of the internal excitation of H2 molecules differ more from thermodynamic equilibrium.
我们报告了在高通量条件下氢原子和分子与冷却铜表面的相互作用及其对气相密度和分子内部激发的影响。这些密度通过使用真空紫外（vuv）可调谐辐射源的激光诱导荧光来测量。虽然通过双光子吸收激光诱导荧光检测到H原子，但通过受激反斯托克斯拉曼散射产生了用于检测处于电子基态的振转激发H₂分子所需的vuv辐射。结果揭示了H原子的一种强烈损失机制以及由于表面相互作用形成振转激发的H₂分子。估计了高通量条件下H原子在铜上的表面反应概率。表面碰撞对振转激发的H₂分子的密度分布有深远影响：这些分布遵循较低温度且不太像玻尔兹曼分布，即H₂分子内部激发的分布与热力学平衡的差异更大。
