CONFORMATIONAL STABILITY OF TETRAFLUOROHYDRAZINE, N2F4

The far infrared (60-350 cm(-1)) and low-frequency Raman (80-150 cm(-1 )) spectra of gaseous tetrafluorohydrazine, N2F4, have been recorded. The fundamental and several excited state transitions of the torsional mode of the gauche conformer have been observed in both spectra. Vari able-temperature (-60 to -90 degrees C) studies of the infrared spectr a of N2F4 dissolved in liquid xenon have been recorded. From these dat a the enthalpy difference has been determined to be 69 +/- 6 cm(-1) (1 97 +/- 17 cal/mol), with the trans conformer the more stable rotamer. Ab initio calculations have been carried out with several different ba sis sets up to MP2/6-311++G from which the structural parameters, con formational stability, harmonic force constants, and infrared and Rama n spectra have been obtained. These quantities have been compared to t he experimental values when appropriate. Some of the fundamentals have been reassigned, and the potential function governing the conformer i nterchange has been determined. The results are compared to the corres ponding results from some similar molecules.