Electronic structure and chemical bond in MdO2

The calculation of the electronic structure of MdO₂ was carried out using the fully relativistic method of discrete variation (RDV), a scheme of molecular orbitals (MO) was built and a histogram of the spectrum of X-ray photoelectron spectroscopy (XPS) was constructed in the range of electron binding energies (BE) 0–∼40 eV. It was discovered that the complex structure of the XPS spectrum of valence electrons is associated with the formation of the outer valence molecular orbitals (OVMO, BE from 0 to ∼15 eV) and of the inner valence molecular orbitals (IVMO, BE from ∼15 to ∼40 eV). The effective charge of Md in MdO₂ calculated from the MO compositions was equal to +0.50 electrons. IVMO electrons were found to weaken the bond formed by OVMO in MdO₂ by ∼34%.