Computational chemistry: A way to reach spectroscopic and thermodynamic data for exotic compounds

In this paper, we report a general methodology to reach thermochemical properties of molecules in gas phase. We applied these calculations to related complexes of industrial interest, concerning the electrowinning of aluminum. This thermochemical prediction is a demonstration of a quantitative analysis after geometry optimizations and frequencies calculations from density functional computations (or any first-principle techniques). Since this methodology is completely generic, we can study any complexes of interest in order to study the model of the vapor. We have especially investigated the (Na3AlF6, Na(2)ALF(5), NaAlF4, AlF3, NaF, (NaF)(2), (NaAlF4)(2)) system. It has been found that NaAlF4 and (NaF)(2) are the major species present in gas phase. Results concerning calcium are also presented, showing that CaAlF5 is in the vapor. Its partial pressure decreases when the one of CaF2 increases and the partial pressure of NaAlF4 (and all minor species containing aluminum) decreases at the same time.