GF CALCULATION WITH MINIMAL AND EXTENDED BASIS SETS FOR H2O NH3 CH4 AND H2O2

A method is proposed for applying the theory of generalized group functions to SCF-GF calculations with large basis sets. A simple procedure for localising the SCF-MO's resulting from a standard SCF calculation is described, with applications to H2O, NH3, CH4 and H2O2. Results compare quite favourably with those obtained by the usual GF method. It is shown that when basis functions are the SCF-MO's and there are only two functions per group, the GF approach is practically equivalent to a configuration interaction treatment where only double excitations within the groups are considered. © 1969 Springer-Verlag.