  Lattice relaxations, surface phonon spectra, surface energies, and work
functions are calculated for Rh(100) and Rh(110) surfaces using
density-functional theory and the full-potential linearized augmented plane
wave method. Both, the local-density approximation and the generalized gradient
approximation to the exchange-correlation functional are considered. The force
constants are obtained from the directly calculated atomic forces, and the
temperature dependence of the surface relaxation is evaluated by minimizing the
free energy of the system. The anharmonicity of the atomic vibrations is taken
into account within the quasiharmonic approximation. The importance of
contributions from different phonons to the surface relaxation is analyzed.
