Satellite bands and the ion states of formamide

Abstract

The core and valence ion states of planar formamide have been studied using a combination of multi-configuration self-consistent field theory and configuration mixing techniques. Emphasis is placed on the location and (for core ion states) intensity of satellite or shake-up states to be found in the X-ray and ultraviolet photoelectron spectra of formamide. It is concluded: (1) The first satellite state is to be identified with the ≈17.8 eV shoulder observed experimentally in the valence photoelectron spectrum and is due to a simultaneous one electron ionization from the 10a′ molecular orbital and a 2a″(π 2) → 3a″(π 3 *) excitation. (2) The lowest energy satellite bands accompanying the K-shell ionization primary photolines for carbon, nitrogen, and oxygen atom spectra are also due to simultaneous π 2 → π 3 * excitations and should appear with uniformly increasing intensity in that atom order. Simple model explanations are given of the calculated energy and intensity trends.