A REDETERMINATION OF THE 1B2U-]1A1G FLUORESCENCE QUANTUM YIELD OF BENZENE VAPOR

The fluorescence quantum yield of benzene vapor excited at 253.7 nm and at pressures from 10 to 50 Torr has been determined at 22-degrees-C by comparison with the fluorescence from a dilute solution of benzene in cyclohexane. The value thus obtained is 0.044 +/- 0.006, which is significantly lower than has been reported in all previous investigations. Although the origin of the discrepancy remains unknown, a theoretical argument is presented that tends to support the lower value.