Satellite peaks in the high energy photoelectron spectra of some small first row molecules

Abstract
The gas phase high energy photoelectron spectra of CH4, NH3, H2O, N2, O2, CO and CO2 have been recorded, and in all cases weak satellite peaks to high binding energy of the main ionization peak are observed. These peaks are assigned to transitions to ionic states in which valence electron excitation as well as core ionization has occurred. The intensity and position of these peaks, relative to the main ionization peak have been estimated from ab initio UHF calculations on the core hole states, which in general allow assignment of the satellite peaks in terms of orbital transitions of the core hole ion.