Direct optimization of orbitals for multiconfiguration self-consistent field theory by unitary transformations

Abstract

In this paper the orbital variations which make stationary the MCSCF energy are generated by unitary transformations worked out directly from the null-gradient condition. A number of iterative procedures are given, compared with other recent proposals and tested numerically on LiH for SCF and geminal theory. A satisfactory convergence rate is found, particularly for the MCSCF case.