ИСТИНА

Despite the fact that the projection population analysis technique, proposed in [1], possesses some advantages, including weak dependence on basis set and excellent compatibility with relativistic treatment of molecular systems, it strongly depends on reference atoms configurations. As a consequence, projection analysis upon Kohn-Sham atomic orbitals can underestimate populations of virtual atomic spinors. In order to make population analysis less sensitive to reference atomic states, a new iterative approach, based on average-of-configuration open-shell Kohn-Sham method, was proposed. In this scheme populations of atomic spinors are obtained in self-consistent manner, hence spatial parts of low-lying virtual atomic spinors can be slightly optimized and become more compact. This new iterative projection analysis (IPA) was applied to molecules of superheavy elements (Cn-Fl) and their lighter homologues (Hg-Pb). We found that IPA possesses full independence on starting atomic orbitals and converges very rapidly. Moreover, the removal of polarization contribution by transformation of molecular pseudospinors IAOs [2] does not affect the results. IPA clearly shows the features of chemical bonding in fluorides and oxides of heavy elements, e.g. using the results of IPA we can conclude that chemical bonds in HgO and HgF 2 are formed by 6s-electrons of Hg atom. In contrast, the bonds in Cn compounds receive significant contributions from d 5/2 spinors, this conclusion is consistent with the fact that in Cn atom 6d 5/2 spinor is higher in energy that 7s-spinor. Furthermore, IPA confirms that d- and s-electrons are inactive in bond formation in compounds of Hg and Fl. To sum up, iterative projection analysis can be used as a rather powerful tool for investigation of bonding in heavy-atom molecules.