Behavior of the Chemical Potential in Calcite and Magnesite Crystals: A Damped Harmonic Oscillation

The behavior of the chemical potential of the species CaCO3 and MgCO3 in proximity of the (10.4) crystal face of calcite and magnesite is determined at the quantum–mechanical level by adopting a recent calculation strategy conceived in our research laboratory. A very peculiar trend of this quantity from the (10.4) surface to the center of the calcite and magnesite crystals was observed. The highest value of the chemical potential is related to the surface layer, while the lowest one is in correspondence to the underlying layer. Interestingly, the chemical potential converges to the bulk value via a damped oscillatory behavior (DOB). We observed that such DOB is strongly related to the structural modification of the slab caused by the presence of the surface, which produces a damped oscillating behavior of the interplanar distances, d10.4, very similar to the one described for the chemical potential. The implications of this finding are discussed.