Knowledge Bank

The Fourier-transform microwave molecular-beam spectrum of the higher energy, polar, gauche- conformer of 1,1,2,2-tetrafluoroethane (Freon 134) has been obtained. Data were gathered for both the normal isotopomers, and the $mono-13C$ substituted compound. The ground vibrational state rotational constants, the molecular structure, and the electric dipole moment were calculated. By using quadrupole focussing fields with bolometric detection and a $CO2$ sideband laser, a molecular-beam IR spectrum of $\nu 6$, the C-C stretch, located at $905cm-1$, was also taken. Although a few strong unassigned lines still exist, the band appears to have no significant perturbations and fits well to a standard asymmetric-rotor Hamiltonian. To study the lower energy, nonpolar, trans- conformer, a molecular jet expansion was used with a diode-laser. Two bands have been observed in the 1125 to $1150cm-1$ region. Analysis of the diode laser spectra is underway.