Semi-elliptical bands

Before considering our model for electrocatalysis, it is instructive to investigate the interaction of a single reactant orbital with a model metal containing a wide. sp-band and a narrow d-hsnA. For this purpose, it is convenient to use the model of a semi-elliptic band [Newns, 1969], for which several important quantities can be calculated explicitly. A single such metal band has the form... 

Plots of the LDOS at the surface (n = 1) site of a 100-atom chain are presented in Fig. 7.3 for various field strengths. For no field, F = 0 (Fig. 7.3(a)), the LDOS exhibits a discretized version of the semi-elliptical shape, familiar for a surface DOS. For small field strength (Fig. 7.3(b)), an almost-linear region appears in the lower end of the quasi-band. As the field strength increases (Fig. 7.3(c) and (d)), the region spreads across the band, with increasing intensities. In addition, there is a rigid shift in the structure to... 

Figure 4.5 shows solutions to the Newns-Anderson model using a semi-elliptical model for the chemisorption function. The solution is shown for different surface projected density of states, nd(e), with increasing d band centers sd. For a given metal the band width and center are coupled because the number of d electrons must be conserved. 

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