Phosphorescence spectra of bromobenzene in highly viscous glassy matrices

Phosphorescence spectra of bromobenzene have been observed in glycerol, 3-m ethyloctane and 4-methylheptane glassy matrices. The phosphorescence quantu m yield has been determined to be ca. 0.03 in glycerol at 77 K. The phospho rescence is composed of two emissions, from (3)pi pi* and (3)pi sigma* to t he ground state. The phosphorescence radiative lifetime is 14 times shorter than that of chlorobenzene and this shortening has been explained by the i nternal heavy atom effect. The non-radiative rate constants were independen t of the solvent species but depended only on the solvent viscosity. The no n-radiative decay rate constant was 10(2) times larger than that of chlorob enzene. (C) 1999 Elsevier Science B.V. All rights reserved.