Chemical Bond Nature and Structure of X-ray Photoelectron Spectrum of PaO2

The relativistic method of discrete variation has been used to calculate the density of states and the X-ray photoelectron spectroscopy spectrum of valence electrons in the range of electron binding energies from 0 to ~50 eV in PaO2. A scheme of molecular orbitals has been constructed. Significant covalence effects are observed in PaO2, which are associated with the overlap of not only Pa6d atomic orbitals but also Pa6p and Pa5f atomic orbitals with oxygen orbitals. It has been found that the electrons of the inner valence molecular orbitals weaken the chemical bond formed by the electrons of the outer valence molecular orbitals.