Shielding of Impurities as Measured by Extended X-Ray-Absorption Fine Structure

Abstract
A new theory of the extended x-ray-absorption fine structure (EXAFS) is presented which avoids the inaccurate approximations of previous ones. It is shown that, in addition to structure determination, EXAFS gives detailed information on the shielding of the singly ionized absorbing atom. Experimental verification of the theory is obtained from EXAFS data for Ge and Cu, explicitly showing shielding oscillations for Cu.