In Surface-Aligned-Reactions (SAR), the degrees of freedom of chemical reactions are restricted and therefore the reaction outcome is selected. Using the inherent corrugation of a Cu(110) substrate the adsorbate molecules can be positioned and aligned and the impact parameter, the collision miss-distance, can be chosen. Here, substitution reaction for a zero impact parameter collision gives an outcome which resembles the classic Newton’s cradle in which an incident mass ‘knocks-on’ the same mass in the collision partner, here F + CF₃ → (CF₃)′ + (F)′ at a copper surface. The mechanism of knock-on was shown by Scanning Tunnelling Microscopy to involve reversal of the CF₃ umbrella as in Walden inversion, with ejection of (F)′ product along the continuation of the F-reagent direction of motion, in collinear reaction.

在表面排列反应 (SAR) 中，化学反应的自由度受到限制，因此选择了反应结果。使用 Cu(110) 基板的固有波纹，吸附分子可以定位和对齐，并且可以选择碰撞参数，即碰撞未命中距离。在这里，零冲击参数碰撞的替代反应给出了类似于经典牛顿摇篮的结果，其中入射质量“敲击”碰撞伙伴中的相同质量，此处 F + CF ₃ → (CF ₃ )' + ( F)' 在铜表面。扫描隧道显微镜显示连锁机制涉及 CF _3的逆转伞形如 Walden 反转，在共线反应中沿着 F-试剂运动方向的延续喷射 (F)' 产物。