The ground electronic state of 1,2-dichloroethane II. Experimental investigation of the fundamental and overtone vibrations

Abstract

The absorption spectrum of 1,2-dichloroethane has been recorded under various experimental conditions, between 50 cm -1 and 10 000 cm -1 using Fourier transform spectroscopy, and between 10 800 cm -1 and 17 400 cm -1 using optoacoustic laser spectroscopy. The assignment of the fundamental bands of the trans and gauche isomers was con® rmed using in particular the results of recent ab initio calculations (El Youssou® et al., 1998, Molec. Phys., 94, 461). The ® rst overtone and combination bands were assigned for the ® rst time using a variety of criteria including the band type and, in some cases, the spacing between clumps 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 anharmonic parameters are obtained.