基于模拟退火法的氨分子总能量分析

Global analysis of total energy of ammonia molecule used simulated annealing algorithm

采用模拟退火(simulated annealing,SA)法,依据量子化学从头计算(Ab initio)原理,实现氨分子总能量优化STO-3G高斯基组函数线性系数的过程。研究中以氨分子总能量为目标函数,以高斯基组函数的线性系数为决策变量,同时以氨分子轨道正交性为约束条件,通过模拟退火过程实现氨分子总能量的最小化。退火运算结果表明:应用模拟退火法时目标函数氨分子总能量对于高斯基组函数线性系数的初始选取并不敏感。不同高斯基组函数线性系数经退火运算后,可使氨分子总能量依概率收敛于-72～-91a.u.,本文同时讨论氨分子能量可能有多解性。

The optimization procedures about total energy of ammonia molecule according to STO-3G gauss basis function of Ab initio method was carried out by simulated annealing algorithm with the total energy of ammonia molecule being as object function, the linear coefficient of gauss basis function as decision variables and the orthogonality of molecular orbital as constraint condition. It is indicated that the total energy of ammonia molecule converge to a range of -72 - -91a. u. for all kinds of linear coefficients of the gauss basis function, meaning that the dependence of total energy of ammonia molecule on the initial selection of the linear coefficient of gauss basis function is insignificant. The possibility of multi-solutions was also discussed in this article.