Influence of Solvent-Solute Interact#ins on Molecular Dynamics

这项研究是实验物理化学计划的一部分，应用皮秒和飞秒时间分辨光谱技术研究溶剂化动力学、电子转移反应、振动和取向驰豫以及扩散控制反应。这些研究将阐明溶解分子与其周围环境之间的相互作用如何影响分子的松弛和反应性。利用激光系统在可调谐性、灵敏度和时间分辨率方面的改进，将研究中等分子在各种溶剂中的振动弛豫路径。我们将用一对脉冲激发振动态的相干叠加的拉曼回波技术来检测振动线形的不均匀展宽程度。这样的系统一直在进化，直到第二个脉冲对使振动重新定相。在第二个延迟后，通过第三个激光脉冲诱导的斯托克斯散射来探测相位相干性。我们将研究电荷转移反应中非指数衰减的起源。特别是，我们将探讨非平衡初态在强绝热电子转移反应中的作用。

This research, part of the experimental Physical Chemistry Program, applies picosecond and femtosecond time resolved spectroscopic techniques to the study of solvation dynamics, electron transfer reactions, vibrational and orientational relaxation, and diffusion controlled reactions. These studies will elucidate how the interactions between dissolved molecules and their surroundings influence molecular relaxation and reactivity. The pathways of vibrational relaxation of medium-sized molecules in a variety of solvents will be investigated by taking advantage of improvements in tunability, sensitivity and time resolution of laser systems. The extent of inhomogeneous broadening in vibrational lineshapes will be examined by using a Raman echo technique in which a pair of pulses excite a coherent superposition of vibrational states. Such a system evolves until a second pulse pair rephases the vibrations. After a second delay the phase coherence is probed by Stokes scattering induced by a third laser pulse. The origin of nonexponential decays in charge transfer reactions will be studied. In particular, the role of a non-equilibrium initial state in strongly adiabatic electron transfer reactions will be explored.