Kr3d52:3d32branching ratio from 97 to 200 eV

The Kr $3d_{\frac{5}{2}}:3\mathrm{}{d}_{\frac{3}{2}}$ branching ratio has been measured between 97 and 200 eV photon energies using monochromatized synchrotron radiation from the Tantalus storage ring. The branching ratios have been obtained both from the Kr $3d_{\frac{5}{2},\frac{3}{2}}$ photolines, and from the Kr $M_{4,5}{N}_1{N}_{2,3} \left({}_{}{}^1{}_{}{}^{}P_1^{}{}_{}{}^{}\right)$ Auger lines in the low- and high-photon-energy ranges where the direct photoelectron measurements are very difficult. The agreement between results for the two methods is very good. In contrast with the Xe $4d_{\frac{5}{2}}:4\mathrm{}{d}_{\frac{3}{2}}$ branching ratio, the Kr $3d_{\frac{5}{2}}:3\mathrm{}{d}_{\frac{3}{2}}$ ratio is almost a constant and very close to the statistical value of 1.5 throughout the energy range studied. Our results are not in good agreement with the theoretical relativistic random-phase approximation results which predict a variation of the $3d_{\frac{5}{2}}:3\mathrm{}{d}_{\frac{3}{2}}$ ratio of 1.4-1.7 between 100 and 120 eV, due to an initial decrease in $3d$ cross sections to 105 eV followed by a slow increase. Our results show that the $3d$ cross sections increase immediately above threshold.