Lattice dynamics and thermodynamic functions of a CaF<inf>2</inf> slab with (110) free surfaces

We present results of lattice dynamical calculations for a eleven layer CaF2 slab with (110) free surfaces. From a comparison with earlier results for NaCl and CsCI structured slabs, we find that new surface modes appear both in the optical and acoustical range of frequencies. The additional modes occur due to the presence of the Raman active band. Results pertaining to the contribution of the surface vibrational modes to the thermodynamic properties are presented. © 1980.