Unoccupied-Band Narrowing in Na and its Effect on the X-Ray-Absorption<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>K</mml:mi></mml:math>Edge

Abstract

The first Na $K$-edge absorption measurements are reported. The data reveal a narrowing of the unfilled density of states analogous to that observed in a recent photoemission study of the conduction band and in very good agreement with new band-structure calculations. The narrowing is found to be essential for obtaining compatibility among the $K$-edge threshold exponent, the ${L}_{2,3}$-edge exponent, and the singularity index in core-level photoemission.