Circular dichroism in photoelectron angular distributions for the 7P3/2level of cesium

Circular dichroism in photoelectron angular distributions (CDAD) is used to examine the alignment of the 7${\mathit{P}}_{3/2}$ and 7${\mathit{P}}_{1/2}$ levels of cesium, prepared by absorption of linearly polarized laser radiation. As expected, the 7${\mathit{P}}_{1/2}$ level exhibits no CDAD, whereas the 7${\mathit{P}}_{3/2}$ level shows a significant CDAD signal, although smaller than that predicted by theory. The difference between experiment and theory is attributed to ${\mathit{m}}_{\mathit{J}}$ mixing due to hyperfine coupling during the finite ionization time of the laser pulse.