MICROWAVE SPECTRUM, BARRIER TO INTERNAL ROTATION, STRUCTURE, AND DIPOLE MOMENT OF 1,1,1,2-TETRAFLUOROETHANE

Article abstract of DOI:10.1016/0022-2860(86)80145-4

The microwave spectrum of CF3CH2F has been studied in the 8 to 26 GHz region, with b-type, Q- and R-branch transitions being assigned for the ground vibrational state and first excited torsional state.Relative intensity measurements give a torsional frequency of 108 +/- 18 cm^-1, which lead to a barrier to internal rotation V₃ = 3.3 +/- 0.8 kcal mol^-1.The dipole moments determined from the observed first-second order Stark effect are μ_a = 0.411 +/- 0.009 D, μ_b = 1.75 +/- 0.22 D, and μ_total = 1.80 +/- 0.22 D.Observed moments of intertia suggest that the CF3 group is not symmetrical or its axis and the C-C bond are not collinear.The distance r_F'..._F' is obtained 2.1594 +/- 0.0006 Angstroem, where F' refers to the outer plane fluorine atoms in the CF3 group.