3-Methylene-1,4-cyclohexadiene is a cyclic isomer of toluene. Transition frequencies were taken from
(1) W. Hutter and H.-K. Bodenseh, and A. Kock, 1994, J. Mol. Struct. 319, 73.
Initial estimates of the quartic distortion parameters were taken from an MP2 quantum-chemical calculation by
(2) H. S. P. Müller, 2021, unpublished.
The data set is quite limited. The calculations were therefore truncated at 200 GHz and at J = 60. The calculations should be sufficient for searches in cold environments. Transition frequencies with calculated uncertainties exceeding 0.1 MHz should be viewed with caution.
Spin-statistical weight ratios have been ignored because of the proximity to 1 : 1.
The dipole moment is from (1).