Harry J. Dewey

Fluorescence and phosphorescence of quinoxaline vapor

Abstract Fluorescence and phosphorescence has been detected from quinoxaline vapor using excitation from a high pressure mercury arc. The fluorescent emission originates near 365 nm and shows several vibronic bands. Under similar experimental conditions we have also observed a highly structured phosphorescent emission. The latter emission has been analyzed in terms of the fundamental vibrational frequencies of the ground state.

A comparison of the rate constants for intersystem crossing via S1(π,π*) T(π,π*) and S1(n,π*) T(π,π*) paths

Abstract The rate constants for S1 T intersystem crossing have been determined for rigid glass solutions of phenanthrene and 9,10-diazaphenanthrene at the temperature of boiling nitrogen. For phenanthrene intersystem crossing path is S1(π,π*) T(π,π*) where kisc was found to be (4.8 ± 1) × 106 sec−1. For 9,10-diazaphenanthrene the path is S1(n,π*) T(π,π*) and kisc was found to be less than 1.5 × 107 sec−1. These results are compared with theoretical predictions.

Site-selected fluorescence of bridged [14] annulenes in nitrogen matrix

Abstract Site-selected fluorescence and excitation spectra of two bridged [14] annulenes isolated in solid nitrogen permit a detailed vibrational analysis and show that the previously unassigned “A band” is not a separate electronic transition but a part of the Lb band.