A Contribution to the Theory of Soft X-ray Emission Bands of Sodium

Abstract

A wave-mechanical treatment of the L_{II, III} emission spectrum of sodium is given, taking into account (i) the broadening of the energy levels in the conduction band due to electron collisions (§§ 2-4); (ii) the lowering of the potential energy of the electron about to make transition into an inner shell of an ion, due to electrostatic attraction (§§ 5-6). The first problem is treated in the free electron approximation, using a model suggested by Skinner, and the theoretical curve has a ` tail ', as found experimentally. The calculation shows that a modification of the wave functions of electrons in a free electron model may be required, and this possibility is discussed. In the second problem, the depression in the electron potential is approximated by using a spherical potential well in the neighbourhood of the ion. The first effect proves to be the more important one, and there is good agreement with experiment.