Single- and double-photoionization cross sections of atomic nitrogen from threshold to 31.

Abstract

The relative photoionization cross section of atomic nitrogen for the production of singly and doubly charged ions has been measured from 44.3 to 275 \AA{} and from 520 to 852 \AA{}. The results have been made absolute by normalization to one-half of the molecular nitrogen cross section at short wavelengths. The smoothed atomic nitrogen cross sections \ensuremath{\sigma} can be accurately represented, at short wavelengths, by the equation \ensuremath{\sigma}(Mb)=3.67\ifmmode\times\else\texttimes\fi{}${10}^{4}$${\mathit{E}}^{\mathrm{\ensuremath{-}}2.3}$ as a function of the photon energy E (eV), thereby allowing the cross sections to be extrapolated to the nitrogen K edge at 31 \AA{}.