Photoelectron measurements of the mercury4f,5p, and5dsubshells

Photoelectron spectra of atomic mercury have been taken using photon energies between 50 and 270 eV. The relative cross sections, subshell branching ratios, and angular distribution asymmetry parameters of the $4f$, $5p$, and $5d$ subshells are reported. In addition, the $4f$ asymmetry parameter was measured up to 600 eV. These quantities show dramatic effects accompanying Cooper minima in the $5d$ and $5p$ subshells and a large centrifugal barrier in the $4f\to \epsilon g$ channel. Comparisons are made with relativistic random-phase approximation and Dirac-Slater calculations. Intershell correlations appear responsible for features in the measured $4f$ asymmetry parameter at the $4d$ threshold and in the calculated $5d$ branching ratio at the $5p$ threshold.