A double-focusing electrostatic electron spectrometer has been used to measure the K—LL Auger spectra resulting from electron impact for each of the elements in the gaseous molecules N2, O2, CO, NO, H2O, and CO2. An energy resolution of 0.09% full width half-maximum was normally employed. A method for analyzing these complex spectra is described. It involves the identification of normal and satellite lines. The former are defined as arising from single electron ionization from the K shell without additional excitation followed by an Auger process in which one electron fills the vacancy while a second goes into the continuum, and where all the other electrons remain in their same orbitals. Satellite lines result when extra excitation occurs either in the initial formation of the K vacancy or in the subsequent Auger process. To aid in the identification of these satellite lines, auxiliary experiments have been performed such as the study of discrete energy losses in photoionization due to electron shake-up, and the comparison of Auger spectra produced by monoenergetic x rays. As a consequence of the analyses of the Auger spectra, information has been obtained on (1) the nature of initial excitation processes such as the transition of a K electron into excited discrete states and monopole excitation and (2) the identification of the energy and nature of the ground and excited states of the doubly charged molecular ions. The second ionization potential was obtained for each of the molecules, and in one case, N2, the third ionization potential was estimated. Finally, a brief discussion is made of the possible use of high resolution electron spectroscopy in molecular as well as elemental analysis.

An electron spectrometer which employs double focusing electrostatic plates is described. The photoelectron spectra obtained by bombarding methane, silane, germane, methyl fluoride, difluoromethane, and trifluoromethane with 21.22-eV photons are presented. The experimental ionization energies are compared with theoretical and other experimental data, and molecular-orbital assignments are made for the energy values obtained. Broad double maximum bands were observed in the case of methane, silane, and germane and are discussed in terms of Jahn–Teller distortion for the positive ions. Possible correlation of the methane spectrum with interstellar space data is also discussed.

No abstract

No abstract