NOTE
FIR Laser Stark Spectroscopy of CD 3 F in the n 6 Å 1 Vibrational State successful. From the detuning experiment ( 1 ), the transi-The far -infrared laser Stark spectra of CD 3 F have been studied using the 337mm line of the HCN laser. Numertion with kl Å 4 was found to be above the laser frequency, ous families of absorption lines have been observed for while kl Å 5, 05, 6, and 7 were found to be below the both parallel and perpendicular polarizations up to laser frequency. The first -and second -order Stark shifts 60 000 V / cm. The experimental setup and procedure were calculated as discussed previously ( 2 ). The value have been previously described ( 1 -3 ). The spectra were for the CD 3 F electric dipole moment in the n 6 Å 1 vibrataken at room temperature and a low-voltage spectra of tional state was taken as 1.8771 D ( 7 ), while the Stark CD 3 F, in the parallel polarization, is shown in Fig. 1.
plate spacing was 0.051508 { 0.00005 cm ( 8 ). In the The ground state millimeter-and submillimeter-wave present analysis, only information from the DM Å 0 specspectra of CD 3 F were analyzed by Bocquet et al. (4) and tra has been used, since the DM Å {1 spectra did not the infrared spectra, from 800 to 1200 cm 01 , were investiyield any new information except for confirming the asgated by Halonen et al. (5). From their analysis (5), an signments. In the degenerate vibrational n 6 Å 1 state of accurate set of vibration-rotation parameters for the n 2 , n 3 , CD 3 F, the intensities of lines with k 0 l a multiple of 3 n 5 , and n 6 bands have been derived. In this paper, several have a greater statistical weight ( 9 ) and were used to help pure rotational transitions of CD 3 F for J Å 22 R 21, Dk Å confirm the assigned transitions. The A 1 -A 2 splittings for 0, and Dl Å 0 in the n 6 Å 1 vibrational state have been the observed k -values were calculated to be less than a measured for the first time with parts-per-million accuracy.
few MHz and were not observed in the spectra. Five distinct families were observed in the laser Stark
The assigned quantum numbers, experimental voltspectra of CD 3 F. Using the procedure discussed in Ref.
ages, and net Stark shifts are given in Table 1 for all five ( 2 ), the lower J value involved in the transition was found families. The line frequency of each family was deterto be 21 for all families. From the energy level predictions mined by subtracting the mean net Stark shift from the based on molecular constants for the n 6 Å 1 vibrational laser frequency of 890 760.2 { 0.2 MHz ( 10 ). Table 2 state ( 6 ), kl values for all families were identified as kl gives the measured and predicted ( 6 ) line frequencies Å 4, 5, 05, 6, and 7. Attempts to fit the spectra for J Å for all the observed families. 22 R 21 in the n 2 , n 3 , and n 5 vibrational states were not FIG. 1. Stark absorption spectrum for the J Å 22 R 21, kl Å 5 transition in the n 6 Å 1 vibrational state of CD 3 F in the parallel polarization at l Å 337 mm.