Theory of Chemical Dynamics

加州大学伯克利分校的威廉米勒得到了化学理论、模型和计算方法项目的一个奖项的支持，以探索新的半经典 用于处理电子非绝热过程的初始值表示方法，即，那些涉及几个势能面上的分子动力学（电子态）。振动哈密顿量的Meyer-Miller-Stock-Thoss表示提供了一种行之有效的方法，并在此框架内进行更有效的计算。 一个更雄心勃勃但不太成熟的方法，显示了巨大的希望，在更基本的水平上引入了电子自由度的经典描述，即单个费米子态的创建/湮灭算符。 这种配方正在追求，看看它已经证明了最初非常有前途的性能是保持更普遍。电子非绝热过程的基础上的一些应用程序，是至关重要的许多技术的当前重要性。这些包括在无机纳米材料和光合系统中与太阳能到电能转换相关的光伏过程，以及“分子电子学”领域，例如，电子通过电极之间的各种分子结构的传输。发展的理论描述，允许一个处理非绝热过程的框架内的经典分子动力学模拟方法将使其可行的进行这样的计算更现实的分子模型，从而更富有成效地与实验工作在这些领域。

William Miller of the University of California, Berkeley is supported by an award from the Chemical Theory, Models and Computational Methods program to explore new semiclassical initial value representation approaches for treating electronically non-adiabatic processes, i.e., those involving molecular dynamics on several potential energy surfaces (electronic states). The Meyer-Miller-Stock-Thoss representation of the vibronic Hamiltonian provides one well-established way for doing this, and more efficient ways of carrying out calculations within this framework are pursued. A more ambitious but less well established approach, that shows great promise, introduces the classical description of the electronic degrees of freedom at a more fundamental level, that of the creation/annihilation operators of the individual fermionic states. This formulation is being pursued to see if the initial very promising performance it has demonstrated is maintained more generally.Electronically non-adiabatic processes underlie a number of applications that are crucial for many technologies of current importance. These include photo-voltaic processes relevant to solar-to-electric energy conversion, in both inorganic nano-materials and in photosynthetic systems, and the field of "molecular electronics", e.g., the transmission of electrons through various molecular structures that are junctions between electrodes. Development of theoretical descriptions that allow one to treat non-adiabatic processes within the framework of classical molecular dynamics simulation methodology will make it feasible to carry out such calculations for much more realistic molecular models and thus interact more fruitfully with experimental work in these areas.