VIBRONIC SPIN-ORBIT INTERACTIONS IN 2-NAPHTHALDEHYDE AND 2-NAPHTHYL METHYL KETONE

The phosphorescence of 2-naphthaldehyde and 2-naphthyl methyl ketone is more in-plane polarized in hydroxyl solvents than in hydrocarbon solvents outside the 0, 0 band. The results are attributed to the solvent effects on the second-order spin-orbit coupling involving vibronic interactions between (n, π+) and (π, π+) electronic states. Solvent effects on the polarization of phosphorescence show that the second-order mechanism involving vibronic coupling in the singlet manifold is more important than the one involving vibronic coupling in the triplet manifold, in bringing dipole-allowed character into the phosphorescence of these molecules. The results on the polarization of phosphorescence lead to a 3A′ assignment for the lowest triplet states of these molecules. © 1969 Taylor and Francis Group, LLC.