Magnetic-quadrupole–electric-dipole mixing inL3x-ray transitions of heavy elements

The angular distribution of ${\mathit{L}}_3$ x rays of Th and U ionized by 1.5-MeV protons has been measured and the anisotropy parameters of these lines have been deduced. The ratios of the anisotropy parameters of the different ${\mathit{L}}_3$ lines were found to disagree with the theoretical predictions. For U, the alignment of the ${\mathit{L}}_3$ subshell has been determined from the angular distribution of the L${\mathrm{\alpha }}_2$ line, and from the measured anisotropy of the other ${\mathit{L}}_3$ x-ray lines the magnetic-quadrupole–electric-dipole mixing ratios were deduced. The experimental mixing ratios for the ${\mathit{ns}}_{1/2}$-2${\mathit{p}}_{3/2}$ transitions are significantly larger than the theoretical values.