Promotion energy, 169 table

Table 1 describes the ensuing legislation that was promulgated to promote energy efficient construction as a result of the Arab oil embargo. 

Figure 3.19 illustrates the dependence of Asp on location in the periodic table for each of the first three elements of main groups 13-17. The promotion energy varies with group number in a manner similar to electronegativity (cf. Fig. 3.17). Although Asp is doubtless important, other factors (such as differences in orbital radii) appear to play a role in general spd hybridization.

Finally it has been pointed out that, within the same transition period, the trend in >m.Co is obscured by the different promotion energies to the valence state and a trend different to that in Table 5 has been calculated for the first period (Cr = 54.2 Fe = 58.7 Ni = 45.6 kcal mol" 1) 22SK A similar effect probably occurs on descending a subgroup. 

The spectacular relationship between the nature of the X3 species and the promotion energy shows that the VBSCD is in fact a general model of the pseudo-Jahn-Teller effect (PJTE). A qualitative application of PJTE would predict all the X3 species to be transition-state structures that relax to the distorted X ---X-X and X-X— X entities. The VBSCD makes a distinction between strong binders, which form transition states, and weak binders that form stable intermediate clusters. Thus, the VBSCD model is in tune with the general observation that as one moves in the periodic table from strong binders to weak ones (e.g., metallic) matter changes from discrete molecules to extended delocalized clusters and/or lattices. The delocalized clusters of the strong binders are the transition states for chemical reactions. 

Table I. The Promotion Energies of the Lowest Configurations of the d6-System...

Using the definitions of the orbital electronegativity presented in eqs. (3.5, 4.10 and 4.11) together with the latest experimental values for the ionisation potentials, electron affinities and term values for the atoms, an extensive reevaluation of the atomic valence state promotion energies and electronegativities has been carried out[28-30]. The results obtained are presented in Chart 1 and in more detail in Table 1. 

Koiller and Falicov used this behavior as a basis of a criterion for whether metallic or insulating behavior is to be expected. They estimated the promotion energy per ion as the atomic promotion energy from Table 19-1, weighted by the multiplicity of the parallel and antiparallel spin configurations for example, for NiO the promotion energy is... 

---