X-Ray-Emission Spectrum Of Metallic Lithium

Using improved wave functions, the X‐ray K‐emission spectrum of metallic lithium is computed in the one‐electron band approximation. An adaptation of the multi‐Lagrangian formula is employed in the interpolation required in the density of states evaluation. The shape of the transition probability curve and the gradient of the intensity spectrum at the Fermi energy are investigated in detail. The conclusion is that self‐consistency in the wave functions has a dramatic effect on the X‐ray transition probability. Nozières and de Dominicis' singularity is applied at the threshold to obtain agreement between the experimental and computed spectra. It is found that the value of the cut‐off energy ξ 0 required for correspondence between the two spectra in the threshold region, is of the order of the Fermi energy. This confirms predictions obtained analytically.