The Raman spectrum of gaseous 1,3-butadiene has been photographed with a three-prism glass spectrograph of linear dispersion 15 A/mm near 4358A. Polarization data have been obtained for the liquid. The observed Raman spectrum has been interpreted in some detail in terms of a planar trans-configuration of the molecule. Two fundamentals have been added to previous assignments, and several assignments have been made more specific. It is concluded that at room temperature a small fraction of the molecules have a cis-configuration.
CHARLES M. RICHARDS and J. RUD NIELSEN, "Raman Spectrum of 1,3-Butadiene in the Gaseous and Liquid States," J. Opt. Soc. Am. 40, 438-440 (1950)