Energy-variance extrapolation for high-spin states with fully optimized variation after projection wave functions

Abstract

We have implemented an energy-variance extrapolation method with the variation after projection (VAP) wave functions which are fully optimized. Thanks to the adopted VAP wave functions which are simplified by taking only one projected state for each selected reference state, the present energy variance extrapolation calculation can be easily applied to high-spin states, even over the backbending. Moreover, the energy variance can be calculated very quickly because the required matrix elements are already available in our previous VAP calculations. The calculated results in $pf$ model space have clearly shown that the extrapolated energies for all calculated spin states are very close to the exacted shell model ones within 20 keV.