Internal heavy atom effect on the triplet spin sublevels of the lowest triplet state of naphthalene. II. Intersystem crossing processes from the singlet excited state to the individual spin sublevels of the lowest triplet state

The rate constants of the intersystem crossing from the singlet excited state to the individual triplet sublevels are determined for a series of halonaphthalenes. The heavy atom enchancement is most significant for the rates to the in-plane sublevels and is less significant for the rate to the out of-plane sublevel. The experimental results are interpreted satisfactorily within the framework of current theories of radiationless transitions.