State-dependent gerade/ungerade intensity ratios in the Auger spectrum of N₂

We have applied both high-resolution photoelectron and Auger spectroscopy to study the N 1s core ionization of N₂. From the respective spectra we are able to show that the Auger decay involves delocalized description of core-hole states. Specifically, the Auger spectra of the N 1sσ _g,u core holes to the quasi-stable final states X¹Σ ⁺_g and D¹Σ⁺_u are presented. They exhibit the gerade/ungerade splitting as well as vibrational progressions. The 1sσ_g/1sσ_u Auger intensity ratios are, in agreement with ab initio calculations, ≅2.1 and ≅0.8 for the X and the D states respectively. The large value for the X state can qualitatively be related to the gerade or ungerade symmetry of the Auger electron.