Gradients in valence bond theory

摘要

A gradient method for general valence bond wave functions is presented. The electronic energy is used as a Lagrange multiplier. The derivartives of the normalization and of the first- and secod-order cofactors present in the energy experession have to be evaluated, giving rise to first-,second-, and third-order cofactors. This evaluation is done using an extension of methods described previously The use of gradients is illustrated with some calcuations on orgaic molecules,vi. ethene, 1,4-butadiene, and benzene.