XIV. The distribution of electrons round impurities in monovalent metals

Summary A theoretical investigation is made of the distribution of electrons round a positively charged impurity dissolved in a monovalent metal. Applications are made to dissolved hydrogen, where the impurity is a proton, and to atoms such as zinc, gallium, etc., which are usually considered to contribute their electrons to the conduction electrons. In all cases the positive charge must be screened; and in many cases this is shown to occur through the formation of bound states below the level of the Fermi distribution. The relation of these results to the Hume-Rothery rule is discussed. The ideas introduced are used to calculate the heats of solution of hydrogen and of polyvalent metals in the noble metals, and to discuss the magnetic properties of these alloys. A detailed discussion is given of x-ray emission and absorption, the vacancy left in the x-ray shell being here treated as the positive impurity. In certain cases quantitative predictions are made about the energies of x-ray absorption edges. Discussions along the same lines are given of the optical absorption of the noble metals, and of the x-ray emission spectra of certain alloys.