有机分子的自洽场分子轨道从头计算的通用程序和C,H基组的选择

本文介绍一个适用于中小有机分子的自洽场分子轨道(SCFMO)从头计算通用程序,并对各种C、H基组作了比较研究,提出一个新的最小原子轨道基组。用它试算甲烷分子的电子结构,仅用9个原子轨道(AO)和41个GTO,得到的分子总能量为E=-40.1662hartree,比STO-KG的结果为优。例如STO-6G用9AO-54GTO得到E=-40.1011hartree。甚至比国际通用的Gaussian-70程序所采用的4-31G双ζ基组也有改进,后者用17AO-36GTO得到E=-40.1395hartree。此外,还在S.B.双ζ基组的基础上,在C-H键中间外加浮动键轨道,得到E=-40.1930hartree。

GENERAL PROGRAM FOR AB INITIO SCF MO CALCULATIONS OF ORGANIC MOLECULES AND SELECTION OF BASIS SETS FOR C AND H ATOMS

In the present investigation we have written in Beida 6912 Language a general program for Ab Initio SCF MOcalculations of organic molecules similar to but simpler than Gaussian70. We have also proposed a new minimum atomic orbital basis set for Cand Hatoms, and with the help of this set the total energy of methane molecule can be calculated to be E = -40.1662 hartree superior to those obtained using STO-6G (E = -40.1011) and 4-31G (E = -40.1395). In order to improve the total energy we have put a floating GTOon each C-Hbond and obtained E=-40.1930, quite near the estimated Hartree-Fook Limit E = -40,22 hartree.