Vibrational excitations in soft x-ray emission and core ESCA spectra of NH3

Abstract
Ab initio calculations are performed for the energy surfaces of the ground N ls hole and 3a1 hole states of ammonia in order to investigate the vibrational band profiles in its soft x‐ray emission and core ESCA spectra. Both the N ls and 3a1 hole states are found to be planar. In comparison with the ground state, the N–H bond length is significantly shortened for the core hole state but relatively unchanged for the 3a1 hole state. The results lead to a core ESCA spectrum dominated by a progression of closely spaced vibrational peaks of the pure bending mode and to a 3a1 x‐ray spectrum with excited stretch–bend combination bands.