Angular distribution of fragment ions formed by K-shell excitation of N2 molecule

Abstract

Angular distributions of the fragment ions produced by the K-shell excitation of N2 molecule have been studied by use of a rotatable time-of-flight (TOF) mass spectrometer. The TOF spectra of N+ and N2+ have been measured at 0, 30, 54.7 and 90' by a photoelectron-photoion coincidence method. Asymmetry parameters obtained for N+ and N2+ are equal. The asymmetry parameters at the photon energies corresponding to the transitions from 1s to the discrete molecular orbitals (2p pi g, 3s sigma g and so forth) are consistent with the values expected from the symmetry of the transition. In the region of the shape resonance (around 419 eV), the values of these parameters are smaller than those obtained by theoretical prediction.