【摘要】 本文提出了用原子从头算的 Fock 矩阵和扩展的休克尔规则与分子的单电子哈密顿矩阵合成从头算的初始 Fock 矩阵的方法.此法有助于克服从头算的假收敛点和迭代初期的振荡,获得了预期的电子组态.在非限制的开壳层分子的从头算中,用原子Fock 矩阵分别合成α和β电子的初始 Fock 矩阵,可使α和β电子同时取得预期的基态能级.用此方法计算了 CO、B₂、HF 等一批分子,均取得良好结果.更多还原

【Abstract】 A new method for constructing the starting Fock matrix of Quantum chemistry ab initio calculation is suggested.It consists of atomic Fock matrixes of atoms ab initiocalculations,semi-empirical Fock matrix（using empirical parameters,ato- mic orbital electronegativity and atomic bonding parameters）and Hamiltonian matr- ix of single electron of ab initio calculation.This method can overcome the oscilla- tion and improve the convergency in an iterative process of quantum chemistry ab initio calculations.Good results are obtained using this scheme to calculate a lot of molecules（CO,B₂ HF etc.）.Expected ground electronic states of α—electron and β—electron are simultaneously obtained using this scheme in unrestrictive Hartree- Fock（UHF）calculation for open shell molecule B₂.更多还原