Theoretical Descriptions of Rotation-Vibration Interactions In Polyatomic Molecules

在化学学部理论与计算项目的这个项目中，Sibert教授将对多原子分子的旋转振动状态进行一套全量子力学计算。要预测化学反应的速率，了解这些状态是必要的。计算将包括使用变分和微扰技术的大范围分子。计算的目的是阐明波恩-奥本海默势能面与动力学和光谱学之间的联系，这是由于这些表面上的运动而发生的。待处理的系统包括H2O、SO2、HCN、HCCH、NH3和H2CO。将发展坐标和基集表示法，不仅方便给定势能面谱的计算，而且方便其逆，即给定能谱的势能面计算。所选择的描述旋转振动分子的表示法将专门用于描述某些雅可比坐标不适合的大振幅运动。对这些转变的理解在我们理解和发展反应速率、反应动力学、碰撞能量转移和模式特定效应的理论方面起着关键作用。

In this project in the Theoretical and Computational Program of the Chemistry Division, Professor Sibert will carry out a set of fully quantum mechanical calculations of rotation-vibration states of polyatomic molecules. A knowledge of these states is necessary to predict the rates of chemical reactions. The calculations will encompass a wide range of molecules using both variational and perturbative techniques. The goal of the calculations is to elucidate the connections between Born-Oppenheimer potential energy surfaces and the dynamics and spectroscopy, which occurs as a result of motion on these surfaces. The systems to be treated will include H2O, SO2, HCN, HCCH, NH3, and H2CO. Coordinate and basis set representations will be developed which facilitate not only the calculation of spectra given a potential energy surface, but also the inverse, namely, the calculation of potential energy surfaces given the spectra. The representation chosen to describe the rotating-vibrating molecules will be specifically designed to describe certain large amplitude motions for which Jacobi coordinates are inadequate. An understanding of these transformations plays a pivotal role in our ability to understand and develop theories of reaction rates, reaction dynamics, collisional energy transfer, and mode specific effects.