大体系多电子相关研究中应用群对称定域轨道的构想

大体系多电子相关研究中应用群对称定域轨道的构想周泰锦，刘爱民（厦门大学化学系，厦门３６１００５）关键词：组态相关，多构型自治叠代，多中心积分，群对称定域轨道，对称约化有关原子簇化合物及化学吸附、过渡态、激发态、催化反应等大体系的量子化学研究，对于探讨...

A NEW IDEA ON APPLICATIONS OF GROUP SYMMETRIC LOCALIZED ORBITALS TO THEORETIC METHODS OF COFIGURATION CORRELATION

The VB Molecular orbitais permit applying some of concepts of chemical analyzing molecular wave funetions.By means of these nonorthogonal VB orbitals,the configuration numbers of MC SCF and CI calculations become smaller,because the electron correlation and excitation must satisfy the symmetric condition and neighbourhood condition,However,the calculations of Hamiltonian matrix elements in N electron system are proportional to N!,and are more difficult while N>10. Optimal group symmetric localized molecular orbitais(OSLMOs)have the same symmetry and maxi mum overlapping with corresponding VB orbitals.Therefore,we can only ealculate the important configurations in the process of CI a nd MCSCF,sing the neighbourhood correlation principe. Moreover,the ealculations of matrix elements are simplified due to orthogonalities among OSLMOs. Thus,the MCSCF calculations for large molecules might be carried out by using OSLMOs as configu ration generating orbitals (CGOs).