Band structure, crystal conformation, and hydrogen bond potentials for solid HF

Abstract

The electronic structure of hydrogen fluoride chains is calculated using the small‐periodic‐cluster approach by representing some high‐symmetry points in the Brillouin zone of the infinite solid by the one‐electron energies of a finite periodic structure. The LCAO representation is used for the crystal orbitals, and a self‐consistent calculation is performed. Problems regarding the convergence of the band structure as a function of the number of K‐grid points used to construct the Hartree–Fock elements, the number of interacting neighbors, and the approach to self‐consistency in the iteration cycle are examined. Band energies, ionization potential, cohesive energy, charge, and electrostatic potential distribution are computed. The adequacy of other methods currently used to investigate electronic and structural problems in hydrogen‐bonded solids is discussed in view of the results obtained. The crystal structure is optimized, and the stability of the crystal against unit cell deformations and atom displacements is examined. Potentials for either collective or single proton movements are computed and discussed in view of the experimental vibrational force constants.