Knowledge Bank

This paper represents the first part of a study of the effect of two-electron spin-orbit coupling terms on singlet-triplet transition probabilities in light atoms and light atom containing molecules. The two-electron atomic spin-orbit coupling terms are comparable to the nuclear term for low atomic number including the second row. In the case where intensity can be stolen from N-V transitions which are doubly excited relative to the triplet state, use of a central field from of the spin-orbit Hamiltonian may be invalid for transition probability considerations. Calculations have been made for $n\to \pi \ast S-T$ promotions in azines and carbonyl compounds illustrating that the two-electron terms cannot always be neglected in discussing molecular S-T transition probabilities. Supported by the National Science Foundation.