Core hole decay spectra of the free ${\mathrm{N}}_2$ molecule show evidence for hitherto unobserved molecular resonances both below and above the K-shell photoionization threshold. Based on earlier calculations they are assigned to doubly excited neutral states which could not be seen below threshold in recent high resolution absorption spectra because of the more intense core-to-Rydberg excitations. By calculating the Auger spectrum of core-excited nitrogen atoms, we show that the features are atomiclike.

• Received 4 October 1995

DOI:https://doi.org/10.1103/PhysRevLett.76.2250