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 $l\ensuremath{\rightarrow}l+1$ and $l\ensuremath{\rightarrow}l\ensuremath{-}1$ channels. The $3d$ (which is nodeless), $4d$, and $5d$ excited states show $d\ensuremath{\rightarrow}p$ zeros while the $5d$ also shows the two zeros in the $d\ensuremath{\rightarrow}f$ 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.