High resolution infrared spectroscopic studies of ethylene-1,1-D2

Rotational assignments in the ν6 + ν9 type-A band and the ν9, ν6 + ν11, and ν1 + ν6 type-B bands of ethylene-1,1-D2, recorded at a resolution of ∼0.03 cm−1, enable the ground state rotational constants to be determined much more accurately than previously. A significant change in the A0 constant is noted. All upper states suffer perturbations to their rotational structures. Analyses, excluding the areas of perturbation, still enable the excited state constants to be determined with considerable precision.