Meller-Plesset perturbation theory

K. Raghavachari, J. A. Pople, E. S. Replogle, and M. Head-Gordon,/. Phys. Chem., 94,5579 (1990). Fifth-Order Meller-Plesset Perturbation Theory Comparison of Existing Correlation Methods and Implementation of New Methods Correct to Fifth Order. 

Second-Order Meller-Plesset Perturbation Theory... 

I) Meller-Plesset second order, for closed shea systems (MP2). Second order perturbation theory calculations have been available for many years, and it is well recognised that this is the most straightforward and simple method for the indusion of dynamical correlation effects. It has also theadvantage that ft is a size-consistent method, now recognised to be a much more important crfteria than the variational crfteria of configuration interaction calculations. MP2 only needs the integrals (iai jb), where i,j are occupied orbitals and a, bare virtual orbitals, in the molecular orbital basis. 

GUI = graphical user interface LMP2 = local Meller-Plesset second-order perturbation theory RCI = restricted configuration interaction. 

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