Strong hybridization

Clearly, several aspects of the orbital optimisation remain to be clarified. Firstly a numerical test using a system more complex than Ilj should be made. What happens to 7T orbitals or strongly hybridized orbitals should be also examined. It would be also interesting to explain how the optimisation - as described here - is related to an energy lowering, as well as the practical use of the present description in actual calculations, etc. .. These different aspects will be examined in forthcoming publications. 

Au-substituted /U-Cu-Fe quasi crystalline alloys, a Au and Fe study Replacement of Cu by Au on BCl sites and strong hybridization of Au with A1 neighbors... 

FIGURE 8.10. A representation of the band structure of WO3. The W5d and 02p orbitals are strongly hybridized and correlated with each other, leading to the delocalization of the and t2g levels. Erom He et al. 

Fig. 7 presents another example of a very high-contrast waveguide - a rectangular buried waveguide covered by a gold layer. Strong hybridization of the waveguide mode with the antisymmetric surface plasmon is clearly manifested. 

Detailed studies - band structure calculations, de Haas-van Alphen effect and polarized neutron diffraction - have evidenced the strong hybridization of 5 f bands either with p anions bands (USi3, UGes, USns) or 4d bands (URhs, UIts). 

From an experimental point of view, it appears that the resonant f level is the best starting hypothesis for most U, Np and Pu compounds. Only in some cases of strong hybridization (particularly for Laves phase and AuCua-type structure intermetallics) it will broaden into true bands and we shall try to give criteria for itinerant magnetism. 

Applying this model, the 4f doublet of Th metal would appear to be a typical 5f-transition metal spectrum (i.e., with a split doublet where the 5 fs play the screening role of the d electrons in a d-transition metal). This is consistent with strong hybridization of 5f and (d, s) states as predicted by theory ... 

CeRii4P]2 is a narrow gap semiconductor with a gap of 0.075 eV estimated from electrical transport measurements on polycrystalline samples (Shirotani et al., 1996). XANES measurements indicate trivalent Ce with strong hybridization with ligand orbitals. The gap is presumably formed from the hybridization of the Ce 4f states with the Ru d and P-p orbitals... 

As can be seen in Figure 6, Tc of RM2B2C compounds also much depends on the lattice parameters. As an example the dashed line represents the variation of Tc in a series with non-magnetic elements R. It should be noted that the effects of lattice parameters in Figure 6 cannot be explained by only taking into account the variation of N( p) in the expression (3), caused by the variation of the lattice parameters. In particular in CeN E C and YbN E C superconductivity is suppressed by strong hybridization of 4f electrons with conduction electrons (see Sections 4.2 and 4.12). 

The ability of compound to be hydrolyzed depends on the cation parameters I and % which govern the polarizability of Me - O bond and the formation of strong hybrid orbitals. For d-elements, d-, s- and p-orbitals in the outer electron shells are close to each other by energy. Therefore, d-elements exhibit an increased trend to hybridization with the participation of d-orbitals. This fact, as well as large I and X values, help to form stable complex compounds, while the ability to hydrolysis is closely correlated with the activity to complex formation. 

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