Photoionization of atomic nitrogen

Abstract

Relative photoionization cross sections were measured for atomic nitrogen from 870 to 600 Å at a wavelength resolution (FWHM) of 0.83 Å. Five members of the autoionizing Rydberg series 2s 2p3(5S0)np 4P were observed, and values of the line shape parameters q, Γ, and ρ2 were determined for the two lowest energy transitions (n = 3 and 4). Oscillator strengths were estimated for both transitions after normalizing the present data to absolute photoionization cross section measurements. The results are q = −1.7±0.1, Γ=0.0275±0.003 eV ρ2=0.51±0.04, and f =0.00580±0.00109 for the n = 3 transition and q = − 1.7 ± 0.1, Γ = 0.010 ± 0.003 eV, ρ2 = 0.58 ± 0.15, and f =0.00240±0.00100 for the n =4 transition. The photoionization cross section showed no other structure in the wavelength region from the NI ionization threshold to 600 Å.