Electronic structure ofLiBeH3

Using a molecular-cluster representation, we have studied the equilibrium lattice spacing and the electronic structure of ${\mathrm{LiBeH}}_3$. The former was obtained by minimizing the total Hartree-Fock energies of a number of clusters consisting of up to 15 atoms in a simple cubic as well as a modified perovskite structure. The resulting lattice constant is found to be in fair agreement with the value obtained by Overhauser from an analysis of the powder-diffraction data. The electronic structure of the hydride was investigated by calculating the partial and total density of states, electron-charge density distribution, and ionic character of the constituent atoms in clusters of up to 27 atoms using the local-density-functional theory. The lack of a prominent structure in the density of states at the Fermi energy and the evidence of directional bonding from the electron density map imply that ${\mathrm{LiBeH}}_3$ does not have as much metallic character as previously expected. Thus, the system may not be a high-temperature superconductor if dependent upon conventional mechanisms. The density of states of ${\mathrm{LiBeH}}_3$, on the other hand, bears a strong resemblance to those of the new high-$T_c$ materials.