Advances in Coupled-Cluster Theory with Molecular Applications

约翰·斯坦顿在理论和计算化学项目的支持下，开发和应用量子化学方法来研究势能表面和光谱学。他的研究包括正式方法开发、计算实现和当前感兴趣的实验应用。方法上的发展包括耦合簇理论的解析二阶导数，激发态和开壳理论的梯度。应用包括苯的泛音谱，甲酸阴离子的光电子谱，和碳烯的电子激发态。精确的分子光谱模拟对于研究分子的性质和结构问题是非常必要的。例如，大气和星际物质的光化学理论研究有助于光谱技术对其进行表征和探测。然而，目前的计算方法往往受到限制，因为它们无法处理大分子和/或大区域的势能表面。本研究旨在解决这些不足。

John Stanton is supported by the Theoretical and Computational Chemistry Program to develop and apply quantum chemical methods to the study of potential energy surfaces and spectroscopy. His research contains a mix of formal method development, computational implementation, and applications of current interest to experiment. Methodological developments include analytic second derivatives for coupled cluster theory, as well as gradients for excited state and open-shell theories. Applications include the overtone spectroscopy of benzene, the photoelectron spectrum of the formic acid anion, and electronic excited states of carbenes.Accurate simulations of molecular spectroscopy are often necessary to investigate property and structural issues in molecules. For example, theoretical studies of the photochemistry of atmospheric and interstellar species assist in their characterization and detection by spectroscopic techniques. Current computational methodologies are often limited, however, by their inability to treat large molecules and/or large regions of potential energy surfaces. This research is intended to address these deficiencies.