Knowledge Bank

Fourier transform infrared spectra of methylene fluoride have been recorded with the BOMEM DA3.002 spectrometer at NIST with an apodized resolution of $0.004cm-1$ in the region of the CH stretching fundamentals. Assignments have been made for the asymmetric CH stretching band $\nu 63014cm-1$, More than 400 lines have been assigned in this C-type perpendicular band with quantum numbers up to $Jmax\prime \prime =16$ and $Kmax\prime \prime =12$. The data have been fitted to Watson’s A-type reduced Hamiltonian in the Ist representation to obtain molecular parameters for the upper state. Evidence of perturbations beyond $Jmax\prime \prime =16$, $Kmax\prime \prime =10$ are discernible in the observed spectra. The $\nu 6$ level is expected to be perturbed by the $\nu 1$ fundamental level via coriolis coupling through rotations about the a-axis. Attempts to include the effect of perturbations with the neighboring fundamental and combination levels are underway. The details of the analysis will be presented.