Franckmdash;Condon Factors in Ionization: Experimental Measurement Using Molecular Photoelectron Spectroscopy

摘要

The photoelectron spectra excited by 21.21hyphen;eV photons in argon, krypton, xenon, hydrogen, nitrogen, carbon monoxide, oxygen, and nitric oxide have been rehyphen;examined using a 180deg; magnetichyphen;field electron velocity analyzer. In favorable cases peaks corresponding to vibrational levels in the resulting positive ion are completely resolved giving directly the Franckmdash;Condon factors. Where the vibrational peaks are not fully resolved, the relative order of intensities is apparent and comparison is made with calculations of the Franckmdash;Condon factors. Vibrational structure associated with the second level of nitric oxide is observed for the first time, and this allows an accurate value (15.65 eV) to be attached to the adiabatic ionization potential of this level.