X-RAY-SPECTRA AND CORE HOLE ENERGY CURVES OF SOME DIATOMIC-MOLECULES

Soft X-ray emission spectra of the molecules CO, N2, NO and O2 are examined for the purpose of deriving information on their core hole energy curves. Molecular force constant and equilibrium bond lengths are determined for the core hole species C*O and N2*, and a qualitative analysis is made for CO*, N*O, NO* and O2*. The results show that differences of equilibrium geometries between the core hole states and the ground states are very well reproduced (better than 1 pm) by SCF calculations within the Hartree-Fock formalism. Inclusion of anharmonicity in the Franck-Condon analysis gives a small but significant effect on the best fitted value for the core hole state bond lengths (about 0.5 pm). Oxygen is binding energies determined from the X-ray spectra are shown to agree with ESCA data, in most cases within a few tenths of an eV. Calculated ΔSCF transition energies reproduce the experimental data within a few eV. © 1979.