MATRIX-ELEMENTS OF MULTIELECTRON OPERATOR IN RESTRICTED HARTREE-FOCK THEORY

A theorem has been established for the matrix elements of a general t- electron operator between N-dimensional determinantal wave functions a rising in the solution of the atomic and molecular multi-electron prob lem by the restricted Hartree-Fock (RHF) method (1 less than or equal to t less than or equal to N). The required matrix elements of this op erator are sums of matrix elements over t-dimensional basic determinan tal wave functions. The final results are especially useful in the det ermination of multi-electron properties for atoms and molecules when t he Hylleraas approach in RHF theory is employed. (C) 1998 Elsevier Sci ence B.V.