Eigenfunctions of spin and orbital angular momentum by the projection operator technique

Abstract

A computer program has been written in Fortran IV to produce eigenfunctions of spin and orbital angular momentum (LS functions) by the projection operator technique. The projection operator acts on a Slater determinant built up from symmetry-adapted spinorbitals. When degeneracies exist, it is easy to provide a set of determinants whose projections span the whole degenerate space. In such cases, the LS functions are Schmidt orthonormalized. These functions provide natural partitions of degenerate LS spaces which are useful in the simplification and systematization of atomic calculations. Some representative examples are discussed.