Quadrupole Lines in theK-Series of Ruthenium

The Ru $K{\beta }_4(K-N_{\mathrm{IV}}{N}_{\mathrm{V}})$ and $K{\beta }_5(K-M_{\mathrm{IV}}{M}_{\mathrm{V}})$ lines have been observed with a double crystal spectrometer. The wave-lengths are 559.74 and 566.68 X.U., respectively. $K{\beta }_5$ appears to be a doublet, the weaker component lying at the long wave-length side. The doublet separation of 0.15 X.U. is within the experimental error in accordance with the $M_{\mathrm{IV}}-M_{\mathrm{V}}$ difference. The width of the single components of $K{\beta }_5$ is smaller than the width of $K{\alpha }_1$, i.e., <11 volts. $K{\beta }_4$ is considerably broader, 28 volts. The intensity ratios are $K{\beta }_4:K{\alpha }_1=1:160\mathrm{}$, $K{\beta }_5:K{\alpha }_1=1:400\mathrm{}$. Also a very faint line $K{\beta }_6$ has been observed the intensity of which is 1: 2000 of the intensity of $K{\alpha }_1$. The wave-length of $K{\beta }_6$ is 558 X.U. It cannot be explained by single electron transitions between known Ru levels.