THE GROUND ELECTRONIC-STATE OF 1,2-DICHLOROETHANE - II - EXPERIMENTALINVESTIGATION OF THE FUNDAMENTAL AND OVERTONE VIBRATIONS

The absorption spectrum of 1,2-dichloroethane has been recorded under various experimental conditions, between 50cm(-1) and 10 000 cm(-1) us ing Fourier transform spectroscopy, and between 10 800 cm(-1) and 17 4 00 cm(-1) using optoacoustic laser spectroscopy. The assignment of the fundamental bands of the trans and gauche isomers was confirmed using in particular the results of recent ab initio calculations (El Yousso ufi et al., 1998, Molec. Phys., 94, 461). The first overtone and combi nation bands were assigned for the first time using a variety of crite ria including the band type and, in some cases, the spacing between cl umps of rotational lines. Emphasis is placed on the CH progression of bands. Most of the results concern bands from the more abundant trans isomer, up to the near infrared range. Bands are tentatively assigned to the gauche species in the mid and near infrared regions and to the trans rotamer in the visible range. Vibrational frequencies and anharm onic parameters are obtained.