VIBRATIONAL SPECTRUM AND NORMAL-MODE ANALYSIS OF 1,3-CYCLOHEXADIENE

The IR and Raman spectra of 1,3-cyclohexadiene have been obtained. A vibrational assignment based both on the vapour IR rotational band shapes and Raman depolarization data is given. The assignment is supported by a zero-order frequency calculation, performed by means of a valence force field previously obtained for cyclohexene4, which led to a correct interpretation of the experimental results. The force constants were then refined to obtain a more accurate normal-coordinate description. Only the most significant interaction terms of the zero-order potential parameters were retained in the refinement process in order to keep their number within a practicable limit. © 1969.