CO₂ laser-microwave double resonance and stark lamb-dip spectroscopy of the ν₅ band of CDF₃

The LMDR (laser-microwave double resonance) spectroscopy with an intense electric field was applied to the ν₅ (CF₃ degenerate stretch) fundamental band of CDF₃. The dipole moments and polarizability anisotropies in the ground and ν₅ vibrational states were determined as follows. {A table is presented} where 3σ uncertainties are given in parentheses; the absolute error in the dipole moments is 7 × 10^-5 D, as determined by the accuracy of the OCS dipole moment. The ground state dipole moment agrees with the MBER (molecular beam electric resonance) result. The polarizability anisotropies are accounted for by the sum of the electronic and vibrational contributions. The (2, -1) interaction was found to give remarkable perturbations to some Stark-shifted rotational levels in the ν₅ state. An electric field-dependent interaction of the (2, -1) type also gives appreciable perturbations. The constants for this interaction, as well as for the ordinary (2, -1) interaction, were determined. The sign of the l-type doubling constant q₅ was determined by the LMDR method. Precise values of other molecular constants were also determined from LMDR and Stark Lamb-dip spectra.