Structure and dynamics from combined neutron scattering and first-principles studies Original Research Article

Using combined first-principles and neutron-scattering techniques, we have studied the structural and dynamical properties of several materials including solid cubane and protonic-conducting oxides. The measured lattice parameters, atomic positions, and vibrational densities-of-states are compared with those obtained from first-principles calculations. In most cases, good agreement was obtained, even for systems as diverse as molecular solids and oxides. In particular, using the van der Waals solid cubane, we tested density functional theory within the local density approximation (LDA) and the generalized gradient approximation (GGA). While calculations within the LDA are in good agreement with the experimental data, GGA calculations predict too large a lattice constant and too small a cohesive energy for solid cubane.