K-MMradiative-Auger transition rates for argon

We present the results of the first calculation of the spectral distribution of emitted photons following $K$-$\mathrm{MM}$ radiative-Auger transitions in the free argon atom. The calculation is based on second-order perturbation theory, and the total transition rate found to be $\frac{2.68\times {10}^{-4\mathrm{}}}{\hslash }$ eV, or 4% of the calculated $K{\beta }_{1,3}$ rate of $\frac{6.7\times {10}^{-3\mathrm{}}}{\hslash }$ eV. The calculated rate and photon spectrum agree fairly well with the experimental data of Keski-Rahkonen and Utriainen. Difficulties which preclude a direct comparison between theory and experiment are discussed, especially the effects of the spectrometer response function on the experimental data. The need for more high-resolution data is emphasized.