Spectra of isomeric a-chloro fluorotoluenes in vapour state

Department of Physics, Satish Chandra College, Ballia, Department of Physics, SMMT Postgraduate College, Ballia, Department of Physics, University of Gorakhpur, Gorakhpur, UP, India , India.

Abstract

Electronic spectra of A-chloro, 2-fluoro, (ortho isomer), A-chloro, 3-fluoro (meta isomer) and A-chloro, 4-fluoro- loluene (para isomer) molecules are investigated in near ultraviolet. Infrared spectra of these molecules in liquid state are also recorded and analysed to support the ultraviolet data. The (0, 0) hands in the electronic spectra are assigned at 2 715.1 A (36 816 cm^-1), 2 721.8 A (36 730 cm^-1) and 2 702.3 A (36 995 cm^-1) in the three isomers respectively. The absorption bands in the ortho isomer are explained in terms of the ground state fundamentals 203, 297, 419 and 541 cm^-1 and the excited stale fundamentals 109, 236, 316, 463, 633, 708, 950 and 1 277 cm^-1. The hands in the meta isomer are analysed in terms of the ground state fundamentals 164, 223 and 300 cm^-1 and the excited state fundamentals 187, 355, 448, 634, 687, 969, 1 173 and 1 271 cm^-1. The fundamentals determined in the para isomer are 188, 476, 511 and 635 cm^-1 in the ground slate and 391, 457. 552. 619, 804, 1 185 and 1 233 cm^-1 in the excited stale. The order of red shift in the (0, 0) bands of the isomeric A-chloro fluorotoluenes is mela > ortho > para.