Theoretical Studies of Electronic Structure and Dynamical Aspects of Electronically Nonadiabatic Processes

理论和计算化学计划是支持教授。 在接下来的三年里，约翰霍普金斯大学的Yarkony。 Yarkony的 研究将集中在有关电子的基本问题 电子非绝热过程的结构方面。 的 特别感兴趣的将是圆锥形的点的轨迹。 交叉，特别是两个相同对称性的状态。 的 锥形交叉口的普遍性和影响将在 在随后的补助期内，调查他们在电子 非绝热过程 第二个基本问题是关于非绝热的 通常用于研究非绝热过程动力学的基础。 虽然经常使用，但非绝热碱仅以近似的形式存在。 道理啊 导数耦合的线积分可用于 确定导数联轴器的不可拆卸部分的尺寸， 这是即使在中也必须保留的衍生耦合部分 “最不正常”的基础。 Yarkony将使用这种技术来识别 导数耦合的不可移除部分 很可观。 对于这些系统，他将使用从头算导数 耦合，以构建“最非绝热”的基础，并比较结果 通常使用但必须近似的糖尿病化程序。 这项工作预计将提供基本的见解的性质 非绝热基 分子暴露在光下的化学，光化学， 与基态分子的化学性质有着根本的不同。 本质区别在于电子能量的相互转换 通过光激发过程产生振动，旋转和 当分子非线性弛豫时的平移能 基态电子态 虽然非绝热过程是 普遍存在，例如在视觉、光合作用和 平流层臭氧退化，许多基本问题， 需要解决非绝热过程。 的一个主要 非绝热过程的驱动因素是一种称为 圆锥相交 曾被认为是罕见的事件 特殊的，对称的，分子的性质，现在很清楚， 非绝热过程本身圆锥形相交是普遍存在的。 Yarkony将使用一种独特的计算机算法系统， 约翰霍普金斯大学在过去十年中研究的基本问题 与圆锥形交叉点以及它们影响 非绝热过程

The Theoretical and Computational Chemistry Program is supporting Prof. Yarkony at Johns Hopkins University over the next three years. Yarkony's research will focus on fundamental questions concerning the electronic structure aspects of electronically non-adiabatic processes. Of particular interest will be the locus of points of the conical intersection, particularly of two states of the same symmetry. The prevalence and impact of conical intersections will be studied in the ensuing grant period to investigate their role in electronically non-adiabatic processes. A second basic question concerns the diabatic bases routinely used to study the dynamics of non-adiabatic processes. Although routinely used, diabatic bases exist only in an approximate sense. Line integrals of the derivative coupling can be used to determine the size of the nonremovable part of the derivative coupling, that is the portion of the derivative coupling that must remain even in the 'most diabatic' basis. Yarkony will use this technique to identify systems for which the nonremovable part of the derivative coupling is appreciable. For these systems he will use the ab initio derivative couplings to construct the 'most diabatic' basis and compare the results with commonly used but necessarily approximate diabatization procedures. This work is expected to provide fundamental insights to the nature of diabatic bases. The chemistry of molecules exposed to light, photochemistry, is fundamentally different from the chemistry of ground state molecules. The essential difference lies in the interconversion of electronic energy created by the photoexcitation process into vibrational, rotational and translational energy as the molecule relaxes non-adiabatically to the ground electronic state. Although non-adiabatic processes are ubiquitous, occurring for example in vision, photosynthesis, and stratospheric ozone degradation, many basic questions concerning non-adiabatic processes need to be addressed. One of the principal drivers of non-adiabatic processes is a topological feature known as a conical intersection. Once thought to be rare occurrences attributable to special, symmetry, properties of a molecule, it is now clear that like non-adiabatic processes themselves conical intersections are ubiquitous. Yarkony will use a unique system of computer algorithms developed at Johns Hopkins University over the last decade to study fundamental issues related to conical intersections and the way they influence non-adiabatic processes.