Generality and Systematics of Multiple Minima in Photoionization Cross Sections of Excited Atoms

Abstract

Multiple zeros in the dipole matrix elements for photoionizing transitions in excited atomic $d$ states are predicted over a broad range of $Z$ for both $l\to l+1\mathrm{}$ and $l\to l-1\mathrm{}$ channels. The $3d$ (which is nodeless), $4d$, and $5d$ excited states show $d\to p$ zeros while the $5d$ also shows the two zeros in the $d\to f$ channel. The variation of the location of these minima with $Z$ is discussed and analyzed in terms of quantum defect theory and some implications are pointed out.