Calculations of X-ray fluorescence of CO and CO2

A recently proposed method for calculating intensities of molecular radiative transitions has been applied for soft X-ray fluorescence, absorption and emission spectra involving core ionized and core excited states of CO2 and CO. The initial carbon and oxygen core states and final valence states are described by multiconfigurational wave functions separately optimized with sets of molecular orbitals that are mutually nonorthogonal. The assignments of energies and intensities are found to be in good agreement with those obtained in experimental X-ray emission spectra and with those deduced from EELS absorption spectra, the latter simulating X-ray absorption, when data on transition energies and oscillator strengths are available. Molecular orbitals and symmetry assignments for emission spectra from neutral core excited states can be proposed based on the present calculations. (orig.)