Fine Structure of X-Ray Absorption Edges

Abstract

IN the issue of the Zeitschrift für Physik for July 2, 1924, Dr. Coster reports the existence of a white line on the long wave-length side of the absorption edge in the case of the higher valence forms of various elements. Evidence has been obtained in this laboratory that iodic acid and potassium permanganate, two of the substances for which he reports this line, are slowly reduced by X-rays. If this occurs in the absorbing screen, it seems reasonable to expect that the photographic plates will show not only the absorption edge of the original compound, but also that of the reduced portion. According to Lindh's results with phosphorus, sulphur, and chlorine, the absorption edge of the reduced form might be expected to fall on the long wave-length side of the main edge. It seems reasonable, therefore, to raise the question whether the white line Dr. Coster reports may not be the absorption edge of that part of the material in the absorbing screen reduced by the X-ray.