Nonadiabatic transition state theory

Nonadiabatic transition state theory (NA-TST) is an extension of traditional transition state theory (TST) that accounts for nonadiabatic effects during a chemical reaction. In classical transition state theory, reactions are modeled as proceeding over an energy barrier, with the transition state being a high-energy configuration that connects reactants to products. The assumption in TST is that the electronic states of the system remain unchanged (adiabatic) as nuclei move through the transition state.