MULTI-PARTITIONING MOLLER-PLESSET PERTURBATION-THEORY - A STATE-SELECTIVE FORMULATION

A state-selective (intermediate Hamiltonian) formulation of the recent ly proposed multi-partitioning Moller-Plesset perturbation theory is p resented. The novel approach offers the possibility to combine the dec ontracted treatment of the reference space parts of wavefunctions with numerical stability in the presence of intruder states and strict sep arability at second order. Test applications to molecular electronic s tructure calculations are considered.