Spin-Dependent Stereochemistry: A Nonadiabatic Quantum Dynamics Case Study of S + H₂ → SH + H Reaction

We study the spin-dependent stereodynamics of the S + H₂ → SH + H reaction by using full-dimensional quantum dynamics calculations with zero total nuclear angular momentum along the triplet ³A″ states and singlet ¹A′ states. We find that the interplay between the electronic spin direction and the molecular geometry has a measurable influence on the singlet-triplet intersystem crossing reaction probabilities. Our results show that for some incident scattering angles in the body-fixed frame, the relative difference in intersystem crossing reaction probabilities (as determined between spin up and spin down initial states) can be as large as 15%. Our findings are an ab initio demonstration of spin-dependent nonadiabatic dynamics, which we hope will shine light as far as understanding the chiral-induced spin selectivity effect.