SYMMETRIZED ROVIBRATIONAL LOCAL STATES FOR TRIPLY DEGENERATE MODES OFSPHERICAL MOLECULES - APPLICATION TO INTENSITY CALCULATIONS IN THE NU(3) LADDER

XY6 octahedral molecules, like SF6, WF6 and UF6, reveal a localized be haviour in the excited states of their stretching mode nu(3). This cha racter may be described through the G superset of U(3) superset of K-3 superset of O-h group chain (Boujut, V., Michelot, F., and Leroy, C., 1998, Molec. Phys., 93, 879). In this paper, we extend our previous t heoretical developments by: the construction of a symmetrized local ro vibrational basis, denoted in; \n; J(eta) \K\Gamma mu], well adapted t o the study of the (n00) states of the nu(3) ladder-the introduction o f an approximate infrared intensity model for the transitions (000) -- > (n00) with n odd. We believe that the simplicity of the analytic exp ressions obtained in each case should facilitate future rovibrational analyses of molecules exhibiting such a localized behaviour, especiall y when the density of states becomes important thigh n and J values). As an illustration, results of simulations, made on the (UF6)-U-238 mo lecule, are presented and discussed.