Matrix effects on the geometry of CaF2 – a consequence of polarization effects?

The structural and vibrational properties of an isolated CaF2 molecule are compared with those calculated for a CaF2 molecule in an Ar matrix. A polarizable ionic interaction model is shown to describe the molecule rather well and to account for the matrix effects on the molecular properties which are apparent when spectroscopic results for the gas-phase and matrix are compared. The polarization of the Ca2+ cation and of the Ar atoms are shown to be crucial effects in stabilizing a non-linear CaF2 configuration in the matrix.