Theoretical Study on the Dynamics of Molecules Under Strong Laser Field

该研究项目的目的是通过分子与强激光场之间的非线性、相干相互作用，发展激光控制化学反应的基础理论。我们主要研究了光子统计效应对分子时间演化的影响、浴诱导多光子过程、强激光场作用下多能级分子的能带理论、相干激光对分子内振动重分布的限制以及强非平稳激光场作用下的光解离机制等问题。我们不仅讨论了孤立条件下的分子辐射相互作用，而且讨论了热浴条件下的分子辐射相互作用。通过大部分的研究项目，在强激光场下的分子动力学的理论处理已经开发没有调用在修饰态表象中的微扰理论。特别是激光相位在控制激光功率中起着重要作用。 关于我们 使用固定激光场进行IVR。强激光场作用下多能级分子的发射多重态结构不能用二能级分子的简单扩展来解释，因为修饰态之间存在干涉效应。本文根据核子波包传播的方法，建立了非稳态强激光场作用下阈上光解的理论处理方法。但是，由于时间的限制，在本计划的期限内，不能发展除简单双原子分子离子以外的多原子分子的激光控制化学反应理论。我们将继续发展激光控制化学反应的理论，并将其应用于分子内质子转移、异构化等感兴趣的化学反应。我们相信，本研究项目所获得的结果将为开展激光控制化学反应的实验提供重要线索。少

The purpose of this research project was to develop a fundamental theory toward the laser control of chemical reactions through the nonlinear, coherent interactions between molecules and strong laser fields. We were concerned with main subjects such as photon statistical effects on time evolution of molecules, bath-induced multiphoton process, spectral band theory of multi-level molecules under strong laser fields, restriction of intramolecular vibrational redistribution (IVR) by using coherent lasers, and photo dissociation mechanism under strong, nonstationary laser fields. We have treated the molecule-radiation intevactions not only under isolated condition but also in the presence of the heat bath. Through most of the research projects, theoretical treatments of dynamics of molecules under strong laser fields have been developed without invoking the perturbation theory in the dressed state representation. Especially, the laser phase has been shown to make an important role in contr … More olling IVR by using stationary laser fields. The emission multiplet structure of a multi-level molecule under strong laser field can not be interpreted in terms of the simple extension of two level molecule because of presence of interference effects between the dressed states. The theoretical treatment of photodissociation above threshold under nonstationary, strong laser field has been established based on the method of the nuclear wave packet propagation. Theory of laser-controlled chemical reaction of polyatomic molecules except simple diatoomic molecule ions, however, could not be developed within the term of this program because of the time restriction. We continue developing the theory of the laser controlling chemical reaction toward application to chemical reactions of interest such as intramolecular proton transfer, isomerization etc. We are convinced that the results obtained in this research project could provide important clue to performing experiments of the laser-controlled chemical reactions. Less