David Z. Goodson, Alexey V. Sergeev
A method is developed for determining the singularity structure of Møller-Plesset many-body perturbation theory from fourth-order perturbation series, using a quadratic approximant with a bilinear conformal mapping. Optimal mappings are determined from extremum conditions. Comparison with accurate singularity positions determined from high-order series for the ground-state electronic energy for a variety of small atoms and molecules shows that the fourth-order method gives a reliable estimate of the singularity structure in the positive half plane, which in practice is usually the singularity structure that most affects the accuracy of summation approximants, and a reasonable estimate of the singularity structure in the negative half plane.
Text of the paper: PDF format.
Results of work at UMassD
Designed by A. Sergeev.