Knowledge Bank

The infrared spectra of the $\nu 2$ and $\nu 3$ fondamental bands of $CDF3$ have been recorded with a high resolution $(0.003cm-1)$ FTIR spectrometer (BRUKER IFS 120HR). The K structure was analysed up to J = 50 for both states : 2488 lines of $\nu 2$ and 1956 lines of $\nu 3$ were assigned. We added also results from a previous analysis of millimeter-wave spectra of the ground, $\nu 2=1$ and $\nu 3=1$ $states1$. Rotational constants and quartic and sextic centrifugal distorsion parameters have been determined accurately. These parameters are much more precise than those reported in previous works. The rotational spectrum of the $\nu 6=1$ state was measured up to 500 GHz and direct $\ell -type$ resonance transitions were observed between 2 and 24 GHz. Two different sets of parameters were used to fit the data because the effective Hamiltonian may be reduced in different ways. The unitary equivalence of both sets of parameters is verified.