COMPARISON OF THE EFFECTIVE-CORE-POTENTIAL AND MODEL-POTENTIAL METHODS IN THE STUDIES ON SPIN ORBIT EFFECTS - ZERO-FIELD SPLITTING OF THE CHI-3-SIGMA- STATE OF PNICOGEN HYDRIDES

Wavefunctions generated by the effective-core-potential and model-potential methods were used with the one-electron part of the correct microscopic spin-orbit Hamiltonian to evaluate spin-orbit contributions to the zero-field splitting of the X 3-SIGMA- state of NH, PH, AsH, and SbH. For both methods, the spin-orbit matrix elements have to be scaled up in order to correct for inadequate description of molecular orbitals near heavy nuclei. After scaling, both methods give very similar description of the fine structure in the ground state.