Photoionization Cross Sections for N and O+

Photoionization cross sections for atomic nitrogen are presented for wavelengths longer than 150 Å. Multichannel expressions, in the dipole approximation, are used to calculate cross sections for ejection of an outer subshell electron. The effect of coupling between final state channels is to bring the dipole velocity and length forms of the cross sections into slightly better agreement with each other. Single channel expressions, in the dipole approximation, are used to calculate cross sections for the ejection of an inner subshell electron. Cross sections, calculated in the dipole velocity approximation, are in good agreement with experimental results of Comes and Elzer, except for wavelengths where autoionization occurs. Photoionization cross sections for singly ionized oxygen are presented for wavelengths longer than 100 Å.