Analytic second derivative techniques for self-consistent-field wave functions. A new approach to the solution of the coupled perturbed hartree-fock equations

摘要: Abstract A new method for the solution of coupled perturbed Hartree-Fock equations is outlined which avoids four-index transformation electron repulsion integrals. This allows extension analytic energy second derivative methods to large molecular systems. The approach has been implemented both closed- and open-shell molecules a number test cases considered, including as many 96 contracted gaussian basis functions. time required determination all cartesian force constants varies from 8% 65% that gradient techniques.