Hamiltonian Matrix Elements for the Table-CI Method Using Genealogical Configuration State Functions
Yuriy G. Khait, Mark R. Hoffmann · ACS symposium series · 2002
All necessary formulas for Hamiltonian matrix elements in the table-CI method are presented in computationally amenable form. In contrast to the initial variant of the method, as developed by Buenker, the obtained formulas allow one to avoid intermediate calculations of separate determinantal matrix elements but instead allows calculation of the Hamiltonian matrix elements directly in the basis of configuration state functions (CSFs). The recently suggested variant of a genealogical scheme for constructing CSFs in the context of table-CI is used, which results in reducing the number of contributions to typical matrix elements by approximately a factor of 2.