ENERGY GRADIENT IN A MULTI-CONFIGURATIONAL SCF FORMALISM AND ITS APPLICATION TO GEOMETRY OPTIMIZATION OF TRIMETHYLENE DIRADICALS

Previous methods of analytic evaluation of the potential energy gradient with respect to nuclear coordinates have been limited to single determinant Hartree-Fock wavefunctions. An expression and a practical method are presented for analytic gradient evaluation for MCSCF wavefunctions of certain widely applicable types. A geometry optimized of trimethylene diradical reaction intermediates has been actually accomplished by the use of the energy gradient for an ab initio MCSCF wavefunction. © 1979.