UNISOFT - A PROGRAM PACKAGE FOR LATTICE-DYNAMIC CALCULATIONS

The program package UNISOFT has been developed for lattice-dynamical calculations. Phonon dispersion curves can be calculated for any crystal structure with up to 20 atoms per primitive cell. The interaction between each individual pair of atoms can be modelled by one or more interaction types such as longitudinal and transverse springs (Born–von Karman model), Born–Mayer potential, Lennard-Jones potential, van der Waals potential, Coulomb potential, shell model. In addition to the model calculation part, UNISOFT contains several auxiliary programs dealing with group-theoretical analysis, neighbourhood analysis, plot of the phonon dispersion, calculation of partial derivatives, check of rotational invariance, calculation of local electrical fields and gradients, calculation of phonon intensities. In combination with a spectrometer for inelastic neutron scattering, UNISOFT provides a tool for the optimization of experiments as well as for a first interpretation of the results. © 1987, Wiley-Blackwell. All rights reserved.