On the Evaluation of the Matrix Elements Between Non-Orthogonal Slater Determinants

摘要

An alternative procedure is presented for the calculation of Hamiltonian matrix elements between non-orthogonal Slater determinants. Using the singular-value decomposition theorem a simple and general expression is derived for the cofactors needed in the Lowdin formula. The algorithm proposed has a cost in terms of CPU time proportional to N4, N being the number of electrons, and does not present any problem of data storage.