Fine Structure in the X-Ray Absorption Spectra of the K Series of the Elements Calcium to Gallium

The K x-ray absorption spectra of the free elements Ca, Cr, Mn, Co, Ni, Cu and Zn have been photographed and for each of these elements an extended fine structure has been obtained. The fine structure, consisting of six or seven secondary edges, extends over an energy range of more than 200 volts. In every instance the element was used as the absorbing screen except Mn where it was present in the alloy manganin. No detectable difference was found in the absorption spectrum of copper between that obtained with a brass screen and that with the element alone. An attempt was made to show more definitely the relation of the Kβ₂ emission line to the principal K absorption limit for Fe, Co, Ni and Cu. Indications are that the main edge is produced by the ejection of a K electron to an optical level rather than to infinity. It is shown that the Kossel theory alone is quite inadequate to explain all the secondary edges. On the basis of multiple ionization the probable electron transitions have been determined and tabulated to account for the observed separations of the various secondary edges from the principal K edge. The methods employed herein to account for probable electron transitions, when applied to the transitions proposed by Ray, in his treatment of the fine structure in K and Ca, give very different energy values from those which he has computed.