【摘要】 CNDO/2一级近似法CNDO/2-FA)是一种值得推荐的方法.此法从Hückel理论所得的密度矩阵出发,构成第一个Fock矩阵,对角化并得到新的密度矩阵后,即转向最后结果的计算.由于略去了自洽迭代,可节省数倍的计算量.已从几何构型、力常数、解离能、电离势、质子亲合势、转动位垒、前线轨道能量等多方面进行考察,一级近似结果皆与自洽结果很相近,仅电荷分布稍不满意.MNDO的一级近似则不可用。更多还原

【Abstract】 The first approximation of CNDO/2,the CNDO/2-FA,is a method worth recommendation. The procedure of CNDO/2-FA is given and the results by FA and those by other methods are listed for comparison.It can be seen that,with the exception of the charge distribution,all data obtained seem to be quite satisfactory.更多还原