Variational cluster methods in coordinate space for small systems: Center of mass corrections made easy

A reexamination of the center of mass problem for light systems in the context of coupled cluster theory has produced a new variational version of the method which is developed entirely in coordinate space. It involves independent cluster functions which depend only on the relative coordinates of the sub clusters of the system. In applications to the ⁴He nucleus described via a number of phenomenological and quasireaIistic microscopic Wigner potentials, the method is shown to be quantitatively rather accurate, producing in all cases almost exact results for the ground-state energies at the SUB(3) level of approximation.