The ground state rotational spectrum of SO2F2

The analysis of the ground state rotational spectrum of SO₂F₂ K. Sarka, J. Demaison, L. Margulès, I. Merke, N. Heineking, H. Bürger, H. Ruland, J. Mol. Spectrosc. 200 (2000) 55] has been performed with the Watson’s Hamiltonian up to sextic terms but shows some limits due to the A and S reductions. Since SO₂F₂ is a quasi-spherical top, it can also be regarded as derived from an hypothetical XY₄ molecule. Thus we have developed a new tensorial formalism in the O(3)⊃T_d⊃C_2v group chain (M. Rotger, V. Boudon, M. Loëte, J. Mol. Spectrosc. 216 (2002) 297]. We test it on the ground state of this molecule using the same experimental data (10 GHz-1 THz region, J up to 99). Both fits are comparable even if the formalisms are slightly different. This paper 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_2vTDS. They are freely available at the URL:http://www.u-bourgogne.fr/LPUB/c2vTDS.html.