Energy dependence of determinantal measures

The concept of determinantal measures, in the context of a generalized Hartree-Fock approximation, is reviewed. The energy dependence of determinantal measures in small model spaces is quantitatively investigated. It is shown that the few-determinant approximation is much better at low excitation energies than for arbitrary states. A parametrization of the determinantal measure versus energy graph is constructed, which demonstrates this enhancement effect, and provides indications for possible extrapolation to larger spaces.