Simulation of Chemical Reactions in Solution With the Combined Quantum Mechanical and Molecular Mechanical Potential

Jaili Gao由理论和计算科学基金会资助。 化学程序进行化学反应的计算机模拟 在溶液中。 结合量子力学和分子力学 正在开发的方法，结合从头算哈特里-福克 和分子轨道技术与统计力学蒙特卡罗 模拟研究溶液中的化学反应， 化学物种 对更复杂的化学物质进行类似计算 物种将采用半经验哈密顿，如AM 1和INDO/S， Monte Carlo模拟技术。 反应是 研究包括3-羧基苯并异恶唑的脱羧和 叔丁基氯在水溶液中的电离。 除了 研究溶液中的化学反应，溶剂对电子的影响， 将使用相同的模型检查发色团的吸收光谱。 计算机模拟溶液中的化学反应提供了重要的 分子水平的洞察力的因素，影响反应速率。 特别是具体的贡献， 极化可以降低化学反应的障碍， 详细研究 许多更有趣的键断裂反应， 然而，表现出不能有效建模量子效应 使用经验势能。 高的方法涉及使用一种 蒙特卡罗和分子轨道联合模拟方法 理论来处理量子自由度经历变化， 化学反应。

Jaili Gao is funded by a grant from the Theoretical and Computational Chemistry Program to perform computer simulations of chemical reactions in solution. A combined quantum mechanical and molecular mechanical methodology is being developed which combines ab initio Hartree-Fock and molecular orbital techniques with statistical mechanical Monte Carlo simulations to study chemical reactions in solution for very simple chemical species. Analogous calculations on more complex chemical species will employ semiempirical Hamiltonians such as AM1 and INDO/S in conjunction with Monte Carlo simulation techniques. Reactions to be studied include the decarboxylation of 3-carboxybenzisoxazoles and the ionization of t-butyl chloride in aqueous solution.. In addition to studies of chemical reactions in solution, solvent effects on electronic absorption spectra of chromophores will be examined using the same model. Computer simulations of chemical reactions in solution provide important molecular level insights into the factors which influence reaction rates. In particular specific contributions which solvation and accompanying polarization make to lowering barriers to chemical reaction can be studied in detail. Many of the more interesting bond breaking reactions, however, exhibit quantum effects which cannot be modeled effectively using empirical potentials. Gao's approach involves the use of a combined simulation approach which uses Monte Carlo and molecular orbital theory to treat the quantum degrees of freedom undergoing change during the chemical reaction.