Campo de Fuerzas Canónico General Anarmónico de Moléculas del tipo XY3 (D3h), XY4 (Td) y XY3Z(C3v)

Abstract

Using VICs to describe molecular vibrations and express forces constants of polyatomic molecules has important advantages, compared with other coordinate systems, because of both a clearer physicochemical interpretation of these constants and the possibility of getting a better comparison and transfer of them among similar molecules. On the contrary, their use can present problems of ambiguity, since the number of VICs defined may be greater than the vibrational degrees of freedom of the molecule. In the 80s, Kuczera present a first solution to the problem of the ambiguity in the harmonic approximation and from the 90s our GI has been working on its implementation and generalization, mainly in the case of branched molecules XYn. This thesis aims to develop and generalize what has been done so far: - Suggesting a general formalism for treating the anharmonic molecular force fields in a canonical unambiguous way by using VICs. - Applying it to the types of branched molecules XY3 (D3h), XY4 (Td) and XY3Z (C3V). - Studying the possible correlations among the canonical force constants of these molecules.