Nonstatistical Ratios of Photoionization Cross Sections for States Split by Spin-Orbit Coupling

From photoelectron spectroscopic studies at 584 {}, the ²D5/2:²D3/2 intensity ratios of Zn, Cd, and Hg have been determined, and the latter two were found to be significantly larger than the statistical value (l+1)/l. Earlier experiments on Ar, Kr, and Xe have yielded ²P3/2:²P1/2 ratios smaller than statistical. We present Dirac-Slater calculations of the partial photoionization cross sections for the J=l±1/2 components of an atomic orbital which show that the ratio is larger or smaller than the statistical value depending on whether the partial cross sections are rising or falling.