M_4,5N_4,5N_4,5 Auger electron spectrum of In from In, InCl and InCl₃ vapours

The high resolution vapour phase M_4,5N_4,5N_4,5 Auger spectrum of indium has been measured from atomic indium and from its mono- and trichlorides. The atomic spectrum reveals fine structure not present in molecular or solid state spectra and has been analysed with the aid of optically known final state energy levels of the 4d⁸5p configuration. Relative intensities and energies of the lines calculated for closed-shell atoms in the ground state using the non-relativistic mixed coupling theory have been compared with experimental values obtained for molecular spectra. Good agreement has been found between experimental and calculated results. Comparison between the present atomic and earlier solid state Auger spectra of indium shows that the kinetic energies are 13.4+or-0.5 eV higher for the metal due to the extra-atomic relaxation.