High-resolution infrared study of collisionally cooled trans-1,2-dichloroethylene

A recently constructed long-path enclosive flow cooling apparatus is employed to obtain the Fourier transform gas-phase infrared absorption spectrum of natural isotopic trans-1,2-dichloroethylene with a resolution of 0.00190 cm(-1) in the 800-1000 cm(-1) spectral region. The rotational structure of the out-of-plane CH flapping fundamental has been analyzed for the isotopic analogues Cl-35(2) and (ClCl)-Cl-35-Cl-37 using the Watson A-reduced Hamiltonian model and I-r-representation. A ground-state combination difference analysis for the (ClCl)-Cl-35-Cl-37 isotopomer based on 1402 assigned transitions belonging to the v(6) band yields a band origin of 897.94493(10) cm(-1) and values for the ground-state rotational constants: A(0) = 1.7466454(44) cm(-1), B-0 = 0.05019643(82) cm(-1) and C-0 = 0.04877977(82) cm(-1) together with quartic centrifugal distortion constants. The red-shift of 0.00444(10) cm(-1) observed for the v(6) band origin of (ClCl)-Cl-35-Cl-37 relative to the Cl-35(2), band origin is now consistent with the Rayleigh rule. (c) 2007 Elsevier Inc. All rights reserved