Subshell branching ratios of partial photoionization cross sections

We examine subshell branching ratios of partial photoionization cross sections, within a relativistic single-electron screened potential, as a function of energy and principal quantum number, for uranium, tin, and carbon. We focus on features beyond the simple kinetic-energy effects made visible by the shift in photon energy, resulting from the fine-structure splitting, which corresponds to the same shape-resonance energy of the outgoing continuum electron. At low energies, deviations from statistical $\frac{\mathrm{}(L+1\mathrm{})\mathrm{}}{L}$ ratios are amplified by the presence and by the separation of Cooper minima in dominant matrix elements. Effects are largest for outer $p$ shells of high-$Z$ elements because the separation of Cooper minima is largest. At higher energies in a given element all the $\mathrm{nL}$ ratios for a given $n$ tend to merge into a common curve.