Spin-orbit configuration interaction using the graphical unitary group approach and relativistic core potential and spin-orbit operators

Spin-orbit configuration interaction (CI) is formulated in terms of the gra phical unitary group approach (GUGA) in combination with relativistic core potential and spin-orbit operators, thus providing an efficient general met hod for treating the electronic structure of molecules containing heavy ato ms. The development of the spin-orbit matrix elements and the implementatio n of these methods in the COLUMBUS suite of programs are described.