The Infrared Absorption Spectra of p-Dichlorobenzene and p-Dichlorobenzene-d4

The infrared absorption spectra of p-dichloro-benzene and p-dichlorobenzene-d4 were measured from 300 to 700 cm−1 in a gaseous state with cesium bromide prism, from 300 to 100 cm−1 in a solid state with gratings, and, using a newly constructed long path (720 cm.) high temperature cell, from 1700 to 700 cm−1 in a gaseous state with a sodium chloride prism. The frequencies and band envelopes of observed absorption bands were reported. On the basis of these results, the assignment of the infrared active normal vibrations of these molecules was determined. The assignment was checked by means of the application of the product rule, and the correctness was verified by the good agreement between the theoretical and experimental values. The assignment was also determined for the observed combination bands, using the Raman fundamental frequencies presented in the previous paper as well as infrared frequencies.