荷兰拉德堡德大学Karman, Tijs团队研究了深非弹性分子碰撞中的光散射。相关研究成果于2022年3月21日发表在《自然—化学》。

对于分子碰撞，分子轨道的偏转提供了对相互作用势最敏感的探针之一，并且有通用的经验法则将偏转方向与预碰撞条件联系起来。根据直觉，前向散射源于掠射碰撞，而近正面碰撞源于后向散射。

该文中，研究人员对非弹性过程中的前向散射进行了观察，该观察违背了这一常识。对于NO自由基与CO或HD分子之间的深度非弹性碰撞，研究人员在完全分辨的成对关联微分截面中观察到前向散射，尽管需要低碰撞参数来诱导足够的能量转移。研究人员通过扩展教科书中考虑非弹性能量转移的硬球散射模型，将这些发现合理化，并将前向散射归因于引力引起的荣耀型轨迹。这种现象，研究人员称之为硬碰撞光散射，据预测是普遍存在的。研究人员推导了硬碰撞光散射发生的条件，并回顾性地确定了以前研究的系统中的这种行为。

附：英文原文

Title: Glory scattering in deeply inelastic molecular collisions

Author: Besemer, Matthieu, Tang, Guoqiang, Gao, Zhi, van der Avoird, Ad, Groenenboom, Gerrit C., van de Meerakker, Sebastiaan Y. T., Karman, Tijs

Issue&Volume: 2022-03-21

Abstract: For molecular collisions, the deflection of a molecule’s trajectory provides one of the most sensitive probes of the interaction potential and there are general rules of thumb that relate the direction of deflection to precollision conditions. Following intuition, forward scattering results from glancing collisions, whereas near head-on collisions result in back scattering. Here we present the observation of forward scattering in inelastic processes that defies this common wisdom. For deeply inelastic collisions between NO radicals and CO or HD molecules, we observed forward scattering in fully resolved pair-correlated differential cross-sections, despite the low impact parameters that are needed to induce a sufficient energy transfer. We rationalized these findings by extending the textbook model of hard-sphere scattering—taking inelastic energy transfer into account—and attribute the forward scattering to glory-type trajectories caused by attractive forces. This phenomenon, which we refer to as hard-collision glory scattering, is predicted to be ubiquitous. We derive under which conditions hard-collision glory scattering occurs and retrospectively identify such behaviour in previously studied systems.

DOI: 10.1038/s41557-022-00907-2

Source: https://www.nature.com/articles/s41557-022-00907-2