The Valence XPS Structure and the Nature of Chemical Bond in CmO2

In the approximation of the relativistic discrete variation method, the valence X-ray photoelectron spectrum of CmO2 was calculated, and satisfactory agreement with the structure of the experimental spectrum was found. It was shown that the structure of the spectrum is due to the electrons of the outer (from 0 to ~15 eV) and inner (from ~15 to ~35 eV) valence molecular orbitals, which leads to an increase in the covalency of the chemical bond in CmO2. The effective charge of curium in CmO2 was determined, and the contribution of various electrons to the chemical bond was evaluated. A semiempirical scheme of molecular orbitals for CmO2 was constructed.