MULTI normally requires a starting orbital guess. In this section we describe how to define
these orbitals, and how to save the optimized orbitals. In a CASSCF calculation, one has
the choice of transforming the final orbitals to natural orbitals (the first order density
matrix is diagonalized), to pseudo-canonical orbitals (an effective Fock-operator is
diagonalized), or of localizing the orbitals.