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Studies on the molecular structure of the v8 band of C2HD3 using high-resolution Fourier Transform Infrared (FTIR) spectroscopy
Author
Luqman Akasyah Zaini
Supervisor
Tan, Augustine Tuck Lee
Abstract
The Fourier transform infrared (FTIR) spectrum of the v8 band of ethylene-d3 (C2HD3) was recorded in the wavenumber region of 820 cm-1 to 1020 cm-1 with an unapodized resolution of 0.00096 cm-1. A total of 1162 infrared transitions were assigned and fitted using Watson's A-reduced Hamiltonian in the Ir representation to derive improved rovibrational constants for the upper state (v8 = 1) up to five quartic centrifugal distortion terms. The full-width at half-maximum (FWHM) of the spectral lines was about 0.0004 cm-1. The root-mean-square (rms) deviation of the fit was 0.00039 cm-1, close to the accuracy (1/10th of the FWHM) of the measurements of the spectral line positions of ± 0.0004 cm-1. Using Watson's A-reduced Hamiltonian, the ground state rovibrational constants of C2HD3 were also determined with a higher accuracy than previously reported, from a fit of 580 ground state combination-differences (GSCDS) from the present infrared measurements, with an rmd deviation of 0,00027 cm-1. The inertial defect was calculated to be 0,06939356(19) μΑ2. The C-type v8 band center of C2HD3 was determined to be 918.731873(27) cm-1. The ground state constants of C2HD3 derived from the experimental GSCD fit were in reasonable agreement with the equilibrium state constants derived from theoretical calculations using the B3LYP/cc-pVTZ, and CCSD(T)/cc-pVTZ levels of theory. The accurate spectroscopic parameters obtained in this study may be used as reference in future works on ethylene, in and beyond the Earth's atmosphere.
Date Issued
2016
Call Number
QD305.H7 Luq
Date Submitted
2016