The v12 band of C2D4

• Main Authors: Tan, T. L., Gabona, M. G., Lebron, Gissela B.
• Format: text
• Published: Animo Repository 2011
• Subjects: Ethylene; Fourier transform infrared spectroscopy; Physics
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/5780
• Institution: De La Salle University

The Fourier transform infrared (FTIR) absorption spectrum of the ν12 fundamental band of ethylene-d4 (C2D4) was recorded in the 1017–1137 cm−1 region with an unapodized resolution of 0.0063 cm−1. Upper state (v12 = 1) rovibrational constants consisting of three rotational and five quartic constants were improved by assigning and fitting 2103 infrared transitions using Watson’s A-reduced Hamiltonian in the Ir representation. The band centre of the A-type ν12 band is found to be 1076.98480 ± 0.00002 cm−1. The present analysis covering a wider wavenumber range and higher J and Kc values yielded upper state constants including the band centre which are more accurate than previously reported. The rms deviation of the upper state fit is 0.00045 cm−1. Improved ground state rovibrational constants were also determined from the fit of 1247 ground state combination differences (GSCD) from the presently-assigned infrared transitions of the ν12 band of C2D4. The rms deviation of the GSCD fit is 0.00049 cm−1. In the rovibrational analysis, local frequency perturbations were not detected even at high J and Ka values. The calculated inertial defect Δ12 is 0.32551 ± 0.00001 μÅ2. The line intensities of the individual transitions in the ν12 band were measured and the band strength of 39.8 ± 2.0 cm−2 atm−1 was derived for the ν12 band of C2D4.