Kα2Kα1Transition Probabilities in Elements withZ<~50

The $\frac{K{\alpha }_2}{K{\alpha }_1}$ transition probabilities have been measured for 22 elements ranging in atomic number from ${}_{21}{}^{}{}_{}{}^{}\mathrm{Sc}$ to ${}_{50}{}^{}{}_{}{}^{}\mathrm{Sn}$, with an estimated error of about 2%. This has been accomplished by bombarding the elements with an electron beam of constant energy, and studying the x-ray emission spectrum. The measured ratios rise gently above the classical limit as the atomic number increases, in contrast to the dip below this limit previously reported for $30\le Z\le 40$. For $Z\ge 30$, the experimental results are in excellent agreement with recent calculations based on the relativistic Hartree-Slater potential. For $Z\le 30$, although experimental results agree with theoretical calculations to within experimental error, they tend to be lower.