High-resolution FTIR analysis and rotational constants for the v12 band of ethylene-1-13C (13C12CH4)

The Fourier transform infrared (FTIR) absorption spectrum of the v(12) fundamental band of ethylene-1-C-13 (or (CCH4)-C-13-C-12) was recorded in the frequency range of 1350-1510 cm(-1) with an unapodized resolution of 0.0063 cm(-1). The upper state (v(12) = 1) and ground state rotational constants derived in the present analysis cover a wide wavenumber range and high J and K-a (J = 41 and K-a = 14). By assigning and fitting 1602 infrared transitions using Watson's A-reduced Hamiltonian in the r representation, upper state (v(12) = 1) constants consisting of three rotational, five quartic and two sextic constants were more accurately determined. The root-mean-square deviation of the fit was 0.00030 cm(-1). Ground state rotational constants were also improved from the fit of 808 ground state combination differences (GSCDs) with a root-mean-square deviation of 0.00032 cm(-1). The unperturbed A-type v(12) band is centered at 1439.34612(2) cm(-1). The inertial defect Delta of 0.05381(8) mu angstrom(2) for the ground state has been derived using the ground state rotational constants obtained from this work. (C) 2014 Elsevier Inc. All rights reserved.