基于电负性均衡方法准确计算杂环分子中的原子电荷  

To calculate atomic charges in heterocyclic molecules based on EEM method

作　　者：叶菲[1] 欧阳永中[1] 梁逸曾[1] 

机构地区：[1]中南大学化学化工学院中药现代化研究中心,湖南长沙410083

出　　处：《计算机与应用化学》2008年第12期1571-1576,共6页Computers and Applied Chemistry

摘　　要：基于电负性均衡方法（EEM），依据原子类型和成键对原子进行细致划分，以准确计算分子中的原子电荷。为准确计算分子中原子的电荷，构建了包含214个分子、含各类不同基团的训练集，采用B3LYP／6-31g^＊基组对分子进行优化并得到各个分子中的原子Mulliken电荷。与其他校正方法将同一类原子视为拥有相同的有效电负性和有效硬度值不同，本文在EEM方程中，依据成键类型和化学环境变化，将C、N、O分别分为为4种、3种和2种不同类型，相应采用不同的电负性和硬度价态标度值，并采用全局优化算法对训练集进行优化以得到各类原子的EEM参数值。本文讨论了这些参数与其他方法所得到的参数的差异，并讨论了本方法与其他校正方法的区别。利用本文校正所得EEM方程参数，对不在训练集中的几个杂环分子的EEM电荷进行了计算，取得了较为满意的结果。A strategy for calculating accurate atomic charges in molecule based on electronegativity equalization method （EEM） is developed in this work. Instead of calculating the average charge values of the atoms in the molecules, different valence states are＇ considered. A large training set containing some small molecules and drug molecules was composed, comprising C, H, O, N and F. Geometries and atomic charges are calculated at the B3LYP/6-31 g^＊ level, and effective electronegativity and hardness values of the atoms concerned in the functional group were calibrated using the Differential Evolution （DE） optimized algorithm, which proved to be an efficient algorithm when used to do optimization. The parameters and charges predicted by these are discussed. The quality of the EEM charges was assessed by comparison with B3 LYP/6-31G^＊ charges calculated four molecules with heterocycle structure, not contained in the training sets.

关 键 词：密度泛函理论 电负性均衡原理 电荷 微分进化优化算法 

分 类 号：O641.121[理学—物理化学]