An alternate well-founded way to treat the center-of-mass correlations:   use of a local center-of-mass correlations potential
  The recently developed "internal" Density Functional Theory provides an existence theorem for a local potential that contains the center-of-mass correlations effects. The knowledge of the corresponding energy functional would provide a much cheaper way than projection techniques to treat these correlations. The aim of this article is to construct such a functional. We propose a well-founded method, suitable for Fermions as well as for Bosons, which does not require any free parameters. 
Jeremie Messud
nucl-th