A diabatization protocol that includes spin-orbit coupling

A diabatization protocol that combines the recently developed model space diabatization scheme and a mean- eld treatment for spin-orbit coupling is presented. The protocol is highly e cient and easy to use. Its robustness is demonstrated in the calculations of the diabatic spin-orbit matrix elements of PH+ 3 , AsH+3 , and SbH+3 . It captures subtle geometry-dependence of the spin-orbit couplings and provides wave function information to explain the origin of the dependence.