Multilayer X‐ray spectrometry in the 20–80 Å region: A molecular orbital analysis of CO and CO2 in the gas and solid states

Abstract

AbstractOptimized multilayer X‐ray spectrometry, using lead myristate and lead stearate analyzers (2d values of 80 and 100 Å) has been applied to the measurement of the O‐‐Kα and the C‐‐Kα spectral bands from CO and CO2 in the gas and solid phases. The LII, III spectra were also measured for argon in the gas and solid states under similar conditions in order to identify and to minimize any non‐molecular components in the CO and CO2 spectra. These molecular orbital data have been related to those obtained with X‐ray and ultraviolet photoelectron spectroscopy and grating X‐ray spectroscopy. The consistency of the results of these complementary measurements is excellent. The ionization energies for the C and O 1s levels have been determined to be 295.4 and 542.0 eV for CO and 296.8 and 540.3 eV for CO2. The MO data have also been compared with that predicted from the symmetry, strength and binding energy of the molecular orbital spectral components as calculated using the currently available computational models, CNDO/2, MINDO/3, MNDO, extended Hückel and ab initio. The molecular orbital calculated results for these organic compounds, CO and CO2, are not in as good agreement with the experimental data as previously demonstrated for molecular orbital spectra measured for C‐‐Kα and the LII, III bands of Cl, S and P for both organic and inorganic compounds.