87 transitions between the vibrational states nu(7) = 1 and nu(8) = 1 of ethylene have been measured in the range going from microwave to submillimetre-waves. The nu(7) = 1 state is already known with an accuracy better than 10(-6) cm(-1) thanks to sub-Doppler CO2 laser sideband spectra. Combining these new measurements with the existing measurements on the nu(3), nu(4), nu(7), nu(8) and nu(10) bands allows us to obtain accurate parameters for the nu(8) = 1 state, including all sextic centrifugal distortion constants and the Coriolis interaction constants up to third order.
Willaert, F., Demaison, J., Margules, L., Mader, H., Spahn, H., Giesen, T., & Fayt, A. (2006). The spectrum of ethylene from microwave to submillimetre-wave. Molecular Physics : an international journal at the interface between chemistry and physics, 104(2), 273-292. https://doi.org/10.1080/00268970500273314 (Original work published 2006)