Resolving the structural dynamics of the initial steps of chemical reactions is challenging. We report the femtosecond time-resolved wide-angle x-ray scattering of the photodissociation of diiodomethane in cyclohexane. The data reveal with structural detail how the molecule dissociates into radicals, how the radicals collide with the solvent, and how they form the photoisomer. We extract how translational and rotational kinetic energy is dispersed into the solvent. We also find that 85% of the primary radical pairs are confined to their original solvent cage and discuss how this influences the downstream recombination reactions.

中文翻译：

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飞秒溶液X射线散射观察二碘甲烷的光解离中的结构演化

解决化学反应初始步骤的结构动力学具有挑战性。我们报告飞秒时间分辨广角X射线散射的二碘甲烷在环己烷中的光解离。数据通过结构细节揭示了分子如何解离为自由基，自由基如何与溶剂碰撞以及它们如何形成光异构体。我们提取平动和旋转动能如何分散到溶剂中。我们还发现85％的伯自由基对被限制在其原始的溶剂笼中，并讨论了这对下游重组反应的影响。