The effect of inversion of the 1s ligand level splittings in gaseous inorganic salts

Using the results of calculations on the electronic structure of a number of molecules and model systems by ab initio and Discrete Variational Xα(DVM-Xα) methods, the inversion in the core level energy splitting of the ligand atoms on going from fluorine- to oxygen-containing inorganic salts in the gas phase is shown. The inversion is connected mainly with the fact that in oxygen-containing salts, such as LiNO₃, TiNO₃, LiClO₄ etc., the effect of pinning up the core levels of bridge oxygen atoms due to electronic density redistribution in the presence of the cation field prevails over the stabilizing influence of the cation electrostatic field. The qualitative notions presented may be used as a guide for the determination of the main geometrical configurations in gaseous inorganic salts and their associated compounds using the X-ray electronic spectroscopy method.