Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford St., Cambridge, Massachusetts 02138, USA.
Faraday Discuss. 2009;142:9-23; discussion 93-111. doi: 10.1039/b910118g.
This introductory article contrasts molecular collisions, particularly reactive collisions, in the familiar "warm" domain with the ultracold regime where the relative deBroglie wavelengths become long compared with the range of interaction of the collision partners. Ultracold collisions have much greater sensitivity to entrance channel interactions, so offer the prospect of tuning by external fields to control onset of reaction. However, for ultracold collisions, kinematic constraints impose severe limitations on the observable dynamical properties. In the exit channel for appreciably exoergic reactions, the deBroglie wavelengths become short, so the exit dynamics are much like those for warm collisions. Reactions of alkali dimers, halides, and monoxide molecules are discussed that seem especially congenial for cold collision studies.
这篇介绍性文章将分子碰撞（特别是反应性碰撞）在熟悉的“温暖”区域与超低温区域进行了对比，在超低温区域中，相对德布罗意波长相对于碰撞伙伴的相互作用范围变得很长。超冷碰撞对进入通道相互作用的敏感性要大得多，因此提供了通过外部场进行调谐以控制反应开始的可能性。然而，对于超冷碰撞，运动学约束对可观察到的动力学特性施加了严格的限制。在可观的放热反应的出射通道中，德布罗意波长变得很短，因此出射动力学与温暖碰撞非常相似。讨论了碱二聚体、卤化物和 monoxide 分子的反应，这些反应似乎特别适合冷碰撞研究。
