Circular-dichroism effects on photoelectron angular distributions for the 7P and 8P states of cesium

Circular dichroism in the photoelectron angular distribution (CDAD) of the 7PJ and 8PJ states of cesium have been measured using plane-polarized light to excite and align the atoms and alternately right- and left-circularly polarized light to ionize them. The experiments are compared with the results of theory, calculated using the Hartree-Fock wave functions with many electron correlations included in the random-phase approximation with exchange. A comparison of theory and experiment allows information on the alignment of the resonant state to be extracted from the experimental data. No CDAD effect is observed for the nP1/2 states that cannot be aligned, whereas CDAD is observed for the 7P3/2 and 8P3/2 states. The CDAD signal is significantly larger for the 8P3/2 state than for the 7P3/2 state, indicating a greater retention of the optical alignment of the 8P3/2 state within the time sampled by the ionizing laser pulse. The differences in the retention of alignment for the two states are attributed to effects of hyperfine depolarization, caused by coupling of the electronic angular momentum to the nuclear spin. copyright 1996 The American Physical Society