Chemical bonding overlap populations

Theoretical studies on the atomic number dependence of the relative effects on chemical bonding, including polonium, have been carried out, " for example PoFg was investigated. An analysis of bond overlap population using both nonrelativistic and relativistic DV-Xa molecular orbital calculations was... 

Chemical bonds between atomic orbitals were extracted with the Mulliken population analysis (36). This analysis is useful for the qualitative discussion of chemical bonding of a series of similar molecules, and has been widely used. In population analysis, the bond overlap population Pb(, 0 for a specific pair of atoms k and I in a polyatomic molecule is defined as... 

In this section, we discuss the way the chemical bonds in the AM and AE tetramers differ in terms of bond overlap populations (Pb)- In the discussion... 

The Atomic-number dependence of the relativistic effects on chemical bonding has been studied using the difference (APb) in the bond overlap populations between the relativistic and nonrelativistic DV-Xa calculations for various XH diatomic hydrides (X=Cu, Ag, and Au) and XFe hexafluorides (X=S, Se, Mo, Ru, Rh, Te, W, Re, Os, Ir, Pt, U, Np, and Pu). The atomic-number dependence of APb suggests that the absolute values of APb roughly increase with order (aZ)2 for Z up to about 80, and the higher order term (aZ) should be... 

KEYWORDS Relativistic effects bond overlap population atomic-number dependence chemical bonding DV-Xa... 

To evaluate chemical bonds and ionic states, the Mulliken populations are useful [14], The overlap charge between atomic orbitals is defined as... 

Ultimately, the treatment of electronic structure in extended systems is no more complicated (nor is it less so) than in discrete molecules. The bridge to local chemical action advocated here is through decompositions of the DOS and the crystal orbital overlap population (COOP) curves. These deal with the fundamental questions Where are the electrons Where can I find the bonds ... 

Fig. 8. Variation of the overlap population of FeS bonds with two Fe-S torsion angles (all Fe -S bond lengths are fixed in 2.29 A). (Reproduced by permission of the American Chemical Society.)...

In the previous paper (13), we have discussed the chemical bonding nature of uranyl nitrate dihydrate and found that the bonding interaction is mainly due to the U 5f, 6d - O 2p components. In the present work, we carry out orbital overlap population analysis to understand contribution of each atomic orbital to the chemical bonding. The orbital overlap populations indicate strength of covalent bonds (19,20). 

First, we examine three kinds of basis sets to clarify the role of the sulfur 3d orbital. The basis sets we test here are Is Sp, ls 3d and ls 4s for S, and we fix F basis set to ls 2p. Table I shows the overlap populations obtained by the Mulliken population analysis for SF2, they clearly indicate the 3d orbital contribution through the change in the sulfur basis set The total overlap population for the ls- 3p basis set is particularly small, while the change in the total overlap population from the ls 3d basis set to the ls 4s basis set is not so large. This result indicates that a Is dp basis set is not suitable for sulfur. In addition, the overlap populations for each atomic orbital pair for the Is 3d and ls 4s basis sets are almost the same, and those involving 4s are very small. We have confirmed that the sulfur 3d orbital is essential for the understanding of its chemical bonding. 

In order to characterize the chemical bonding of sulfur, we analyze effective charges, orbital populations and overlap populations. Table III shows the effective charge of the sulfur atom together with the valence state of sulfur in SF2,... 

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