Use of multi-determinant wave functions as input for standard shell model calculations

We show that the use of wavefunctions obtained with the hybrid multi-determinant method for both the yrast states and the excited states of a given Jπ, as an input for the standard shell model diagonalization method, can greatly reduce the computational cost of large-scale shell model calculations. Few examples are given using the GXPF1A interaction in the fp region.