High-resolution synchrotron FTIR spectroscopic analysis of the Coriolis interaction between the v 10 = 1 and v 8 = 1 states of ethylene- cis -1,2- d 2

The measured FWHM of the lines was about 0.002 cm − 1 . The ν 10 band, centred at 662.871885(27) cm −1 was found to be perturbed through a b- type Coriolis resonance with the infrared inactive ν 8 at 759.9582(20) cm −1 .

In this work, 1989 infrared transitions of ν 10 were assigned for the first time. These perturbed and unperturbed infrared transitions were fitted with an rms deviation of 0.00033 cm −1 using the Watson's A -reduced Hamiltonian in the I r representation with three Coriolis terms to derive the rovibrational constants for v 10 = 1 and v 8 = 1 states. Ground state rovibrational constants up to two sextic terms were also derived from a fit of a total of 2532 ground state combination differences with arms deviation of 0.00030 cm −1 from the infrared transitions of the present analysis and those determined previously.