We have shown, using the fact that glyoxal exists in the trans conformer and the pseudo stable cis conformer, a potential function can be calculated which fits the infrared data of the trans conformer and the microwave intensity data of the cis conformer. This potential function was extended to the d1 and d2 analogs. A study of the potential function of 1,3-butadiene using a different molecular geometry than was previously used was undertaken. Results are presented with different possible vibrational assignments and potential functions which would be consistent with the observed infrared and Raman spectra.