Spectroscopic Studies in the Near Ultraviolet of the Three Isomeric Dimethylbenzene Vapors. II. Absorption Spectra of Meta and Ortho Dimethylbenzene

Abstract

The vapor absorption spectra of meta- and ortho-xylene were obtained with a 3-meter grating spectrograph. The m-xylene spectrum has the least number of bands and the most diffuse appearance. Its 0, 0 band is located at 36955 cm−1. The o-xylene spectrum consists of many very sharp bands, several of which must be assigned to v—v transitions. Its 0, 0 band is found at 37308 cm−1. Vibrational frequencies of 965, 675 and 470 cm−1 are found in the upper level of the meta-spectrum and are correlated with the ground-state frequencies of 995, 725, and 510 cm−1. In the ortho spectrum ground-state vibrational frequencies of 1233, 1054, and 736 cm−1 are correlated with the excited state values 1195, 939, and 692 cm−1, respectively. Assignments of the different frequencies are discussed. The Tesla luminescence spectrum of meta-xylene is interpreted along with the absorption spectrum.