Ultrafast spectroscopy and stochastic dynamics studies of chemical dynamics in solution with high resolution in both space and time have been undertaken for many years, but it is still challenging to connect fundamental knowledge obtained from stroboscopic approaches at ultrashort timescales and small length scales with that obtained by directly measuring individual particle motion at longer timescales. Therefore, it is interesting, conceptually and experimentally, to understand the similarities and differences between these two approaches to the study of chemical dynamics in condensed phase systems. We discuss recent advances in the understanding of the transition from ballistic to diffusive motion and chemical reaction rate theories and describe the significance of the findings in relation to the study of thermally activated processes at multiple time and length scales.

在空间和时间上具有高分辨率的溶液中化学动力学的超快光谱学和随机动力学研究已经进行了很多年，但是将频闪观测方法获得的基本知识与超短时间尺度和小长度尺度相结合仍然是一项挑战。直接在更长的时间尺度上测量单个粒子的运动。因此，从概念上和实验上来理解这两种方法在凝相系统中进行化学动力学研究的异同是很有趣的。