6533b858fe1ef96bd12b57ba

RESEARCH PRODUCT

High-resolution spectroscopy and preliminary global analysis of C–H stretching vibrations of C2H4 in the 3000 and 6000cm−1 regions

subject

description

Abstract Ethylene (ethene, H2C=CH2) is a naturally occurring compound in ambient air that affects atmospheric chemistry and global climate. The C2H4 spectrum is available in databases only for the 1000 and 3000 cm−1 ranges. In this work, the ethylene absorption spectrum was measured in the 6030–6250 cm−1 range with the use of a high resolution Bruker IFS 125HR Fourier-spectrometer and a two-channel opto-acoustic spectrometer with a diode laser. As a secondary standard of wavelengths, the methane absorption spectrum was used in both cases. A preliminary analysis was realized thanks to the tensorial formalism developed by the Dijon group that is implemented in the XTDS software package [39] . We considered the two combination bands ν 5 + ν 9 and ν 5 + ν 11 as an interacting dyad. Parameters for the ν 9 / ν 11 dyad were fitted simultaneously from a re-analysis of previously recorded supersonic expansion jet FTIR data, while parameters for the v5=1 Raman level were taken from literature. More than 600 lines could be assigned in the 6030–6250 cm−1 region (and also 682 in the 2950–3150 cm−1 region) and effective Hamiltonian parameters were fitted, including Coriolis interaction parameters. The dyad features are globally quite well reproduced, even if there are still problems at high J values.