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 t o related complexes of industrial interest, concerning the electrowinn ing of aluminum. This thermochemical prediction is a demonstration of a quantitative analysis after geometry optimizations and frequencies c alculations from density functional computations (or any first-princip le techniques). Since this methodology is completely generic, we can s tudy any complexes of interest in order to study the model of the vapo r. We have especially investigated the (Na3AlF6, Na(2)ALF(5), NaAlF4, AlF3, NaF, (NaF)(2), (NaAlF4)(2)) system. It has been found that NaAlF 4 and (NaF)(2) are the major species present in gas phase. Results con cerning calcium are also presented, showing that CaAlF5 is in the vapo r. Its partial pressure decreases when the one of CaF2 increases and t he partial pressure of NaAlF4 (and all minor species containing alumin um) decreases at the same time.