Manifestation of many-electron correlations in photoionization of the K shell of N₂

It is demonstrated theoretically in the random phase approximation (RPA) that due to the intershell many-electron correlations the σ* shape resonance in the photoionization of K shells of the N₂ molecule appears not only in the 1σ_g → εσ_u channel as it was believed earlier on the basis of single particle calculations, but in both 1σ_g → εσ_u and 1σ_u → εσ_g channels. As a confirmation of this phenomenon we show that the experimental angular distributions of photoelectrons ejected from fixed-in-space N₂ molecules can be reproduced theoretically only after taking into account many-electron correlations.