Goldberg Noah T, Zhang Jianyang, Miller Daniel J, Zare Richard N
Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA.
J Phys Chem A. 2008 Oct 2;112(39):9266-8. doi: 10.1021/jp801187p. Epub 2008 Apr 25.
The differential cross section (DCS) for the reaction H + D2 --> D + HD (v' = 3, j' = 0) exhibits particularly rich dynamics; in addition to the expected direct recoil backscattering feature, a surprising time-delayed forward scattering feature appears that has been attributed to glory scattering arising from nearside and farside interference. This fact leads to a complex DCS that depends strongly on the collision energy. Its accurate calculation requires a fully quantum mechanical (QM) treatment. We report improved measurements of this DCS over the collision energy range 1.55 < or = E(coll) < or = 1.82 eV. Previous measurements using the core extraction method, while generally in agreement with theory, lacked sufficient resolution to capture all of the noteworthy behavior of the system; in the present work, we use ion imaging to observe many previously unresolved features of the DCS, particularly in the forward-scattered region. Agreement with QM calculations is found at all collision energies, reconciling an earlier discrepancy between experiment and theory near E(coll) = 1.54 eV.
反应H + D2 --> D + HD（v' = 3，j' = 0）的微分截面（DCS）展现出特别丰富的动力学特性；除了预期的直接反冲背散射特征外，还出现了一个令人惊讶的时间延迟前向散射特征，这被归因于近侧和远侧干涉引起的荣耀散射。这一事实导致了一个强烈依赖于碰撞能量的复杂DCS。其精确计算需要完全量子力学（QM）处理。我们报告了在1.55 ≤ E(coll) ≤ 1.82 eV碰撞能量范围内对该DCS的改进测量结果。先前使用核心提取方法的测量虽然总体上与理论一致，但缺乏足够的分辨率来捕捉该系统所有值得注意的行为；在本工作中，我们使用离子成像来观察DCS的许多先前未解决的特征，特别是在前向散射区域。在所有碰撞能量下都发现了与QM计算的一致性，解决了先前在E(coll) = 1.54 eV附近实验与理论之间的差异。
