THE GROUND STATE ROTATIONAL SPECTRUM OF $SO_{2}F_{2}$.

Abstract

The analysis of the ground state rotational spectrum of $SO_{2}F_{2}^{a}$ has been performed with the Watson's Hamiltonian up to sextic terms but shows some limits due to the A and S reductions. Since $SO_{2}F_{2}$ is a quasi-spherical top, it can also be regarded as derived from an hypothetical $XY_{4}$ molecule. Thus we have developped a new tensorial formalism in the $O(3) \supset T_{d} \supset C_{2v}$ group $chain^{b}$. We test it on the ground state of this molecule using the same experimental $data^{c}$ (0-1 THz region, J up to 99). Both fits are comparable even if the formalisms are slightly different. This talk intends to establish a link between the classical approach and the tensorial formalism. In particular, our tensorial parameters at a given order of the development are related to the usual ones. Programs for spectrum simulation and fit using these methods are named $C_{2v}$ TDS. They are freely available at the URL: http://www.u-bourgogne.fr/LPUB/c2vTDS.html