Symmetry-resolvedK-shell photoabsorption spectra of freeN2molecules

Abstract
‘‘Symmetry-resolved’’ photoabsorption spectra of free N2 molecules in the K-shell excitation region have been obtained using a technique of angle-resolved photoion spectroscopy combined with linearly polarized undulator radiation. The obtained Σ- and Π-symmetry component spectra have nicely demonstrated the symmetry decomposition of the photoabsorption spectrum. These spectra have been compared with theoretical calculations in the photon-energy regions below and above the ionization threshold.