Metallic Bonding and the Character of Electronic States inNb3Ge andNb3Al

The electronic charge density for ${\mathrm{Nb}}_3$Ge and ${\mathrm{Nb}}_3$Al is calculated using a self-consistent pseudopotential technique. Results indicate that there is charge transferred from Nb and Ge to the interstitial region, suggesting a metallic bonding description of these compounds. The charge transfer from Ge to Nb is not prominent as suggested by the Bongi model. Calculated charge densities for states near the Fermi level suggest that $R$ and $M$ are more sensitive to atomic displacements along the chain than the points $\Gamma$ and $X$ chosen previously to explain $A-15\mathrm{}$ Martensitic transitions.