Techniques Used in Evaluation Orbital and Wavefunction Coefficients and Property Derivatives - eg the Evaluation of M(B)P(T)-2 Second Derivatives

摘要

A report is made on the first evaluation of the analytic second derivative of the second order perturbation energy expression. This is the simplest energy expression, which includes electron correlation, which can be analytically differentiated. This implementation requires the evaluation of all first order orbital changes U(l) sub ji, but eliminates the evaluation of U(2) sub ji. Four index transformations of derivative integrals are required. An application of the method to formaldehyde (42 basis functions) is reported.