The Auger Effect in Relative Intensities and Widths of X-Ray Lines

A systematic study of the widths and relative intensities of certain $L$ lines in the atomic number range $70\le Z\le 81$ has been made with a two-crystal spectrometer. It was found that in going from Ta (73) to Tl (81) the width of lines arising from $L_{\mathrm{I}}$ initial states increased in energy by approximately six electron volts, while the widths of lines arising from $L_{\mathrm{II}}$ and $L_{\mathrm{III}}$ initial states increased by only approximately one electron volt. Further, the intensities of $L_{\mathrm{I}}$ lines relative to the intensities of $L_{\mathrm{II}}$ and $L_{\mathrm{III}}$ lines showed a marked decrease with atomic number. Both of these variations can be attributed to the rapid increase with atomic number of the probabilities of the Auger transitions $L_{\mathrm{I}}\to L_{\mathrm{III}}{M}_{\mathrm{IV}}$ and $L_{\mathrm{I}}\to L_{\mathrm{III}}{M}_{\mathrm{V}}$. The results on line widths are in accord with the theory of Weisskopf and Wigner. All the data recorded indicate that Auger transitions are of prime importance in determining the relative intensities and widths of certain x-ray lines.