$K{\alpha }_{1,2}$ and $K{\beta }_{1,3}$ x-ray emission lines of the $3d$ transition metals

The $K{\alpha }_{1,2}$ and $K{\beta }_{1,3}$ emission spectra of the $3d$ transition metals Cr, Mn, Fe, Co, Ni, and Cu were measured, employing a single-crystal diffractometer optimized for minimal instrumental broadening. The high-accuracy diffractometer, and the interferometrically calibrated silicon crystal employed ensure absolute wavelengths in the metric scale to a sub-part-per-million accuracy. An accurate analytic representation of each line, obtained by a fit to a minimal set of Lorentzians, is presented. The absolute energies, linewidths, and indices of asymmetry, derived from the data, agree well with previous measurements. So do also the intensity ratios $K{\alpha }_2/K{\alpha }_1$ and $K{\beta }_{1,3}/K{\alpha }_{1,2},$ which are, however, slightly, but consistently, higher than previous values. Possible origins for the observed $Z$-dependent trends are discussed.