Analytic Derivative Methods in Molecular Electronic Structure Theory: A New Dimension to Quantum Chemistry and its Applications to Spectroscopy

During the last four decades, there have been many developments in the field of ab initio variational and nonvariational correlated wavefunctions, including nonvariational (yet size extensive) many-body perturbation theory (MBPT) and coupled-cluster (CC) methods. For these methods to be useful in solving problems in chemistry, analytical derivatives of total energies are almost always required. In this article, we first describe the analytic derivative methods for variational wavefunctions, namely, closed-shell self-consistent field (CLSCF), general restricted open-shell SCF (GRSCF), configuration interaction (CI), and general multiconfiguration SCF (MCSCF). Then we describe the more recent developments in analytic derivative methods, including those for the MBPT and CC wavefunctions. Keywords: ab initio; electronic structure theory; variational wavefunctions; MBPT models; coupled cluster models; analytic derivatives; CPHF equations; CPCI equations; CPMCHF equations

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