Complete Structure of Gauche 1,1,2, 2-Tetrafluoroethane Determined by Microwave Spectroscopy
The complete molecular structure of the high-energy gauche rotamer of 1,1,2,2-tetrafluoroethane (TFEA), Freon F134, has been determined using pulsed-molecular-beam Fourier transform microwave spectroscopy. Five different 13C- and 2H-substituted isotopomers, in addition to the normal species, were studied. Unlike the nonpolar anti rotamer, the gauche form has a permanent electric dipole moment, which permits a direct rotational analysis. The electric dipole moment was also determined using the Stark effect of two low-J transitions. The resulting dipole moment is μc = 8.186(7) × 10-30 C m [2.454(2) Debye] where the numbers in parentheses are the standard uncertainties (i.e., 1σ). The experimental results for the geometric parameters of TFEA are compared with two recent ab initio calculations.
Maté, Belén , Angela Hight Walker, R. D. Suenram, and Norman C. Craig. 2000. "Complete Structure of Gauche 1,1,2, 2-Tetrafluoroethane Determined by Microwave Spectroscopy." The Journal of Physical Chemistry A 104(42): 9489-9493.
American Chemical Society
Journal of Physical Chemistry A
Chemistry and Biochemistry