Spinor spin magnetization of valence spinors halogen oxide anions (ClO-, IO- and TsO-). The low-lying electronic states of the halogen oxide radicals arise from ionizations of these orbitals (doi:10.1063/1.5053846). Relativistic effect such as spin-orbit coupling are very important for heavy elements.

A second family of methods treats spin-orbit coupling via a spin-orbit CI (SOCI) [cite EPCISO] approach on the basis of many-electron wavefunctions obtained with approximate relativistic Hamiltonians, describing only scalar relativistic effects (one-component methods). These developments are made on the EPCISO code.