BasisFit

BasisFit extracts molecular orbitals from a GAMESS data file and constructs near-identical orbitals from an alternative basis set using least-squares fitting of the new basis functions to the old.

This is particularly useful for generating physically sensible starting orbitals for CASSCF calculations from atomic minimal basis Hartree-Fock orbitals, but can be used to convert any converged set of orbitals from one basis to another.