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

Abstract

A wave-mechanical treatment of the LII, 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.