RADIATION TRAPPING IN A STEPWISE-EXCITATION ELECTRON-LASER COINCIDENCE EXPERIMENT

The observation of radiation trapping effects in time-resolved, stepwise-excited, electron-photon coincidence signals is reported. Hg atoms were excited by electron impact to the 6(1)P1 state and then by laser excitation to the 6(1)D2 state. Coincidence signals were observed from the 6(1)D2-6(3)1 (313-nm) transition. The decay time of these signals was found to depend upon radiation trapping of the electron-impact-excited 60(1)P1-6(1)S0 (185-nm) resonance line. An explanation of this effect is given in terms of the laser excitation coupling the 313- and 185-nm transitions.