Rovibrational constants for the ground state and ν8=1 state of ethylene-d3 (C2HD3) by high-resolution FTIR spectroscopy

High-resolution FTIR spectroscopy of ethylene-d3 (C2HD3): Rovibrational constants for the ground state and the v8=1 state

“…A strong central Q branch, typical of a C-type band, is present at about 918.73 cm -1 . The signal-to-noise ratio is greater than that of the previous study [4] as expected, allowing for the assignment of a greater number of transitions.…”

“…A background spectrum of the evacuated cell was recorded with a total of 1200 scans at a resolution 0.0063 cm -1 . The ratio of the sample spectrum of C 2 HD 3 to that of the background gave a transmittance spectrum with relatively smooth baseline and a signal-to-noise ratio (S/N) of about 100, which is better than that reported by Tan and Lebron [4].…”

“…By assigning and fitting more infrared transitions for the  8 band and by fitting combination-differences derived from the infrared transitions using Watson's Hamiltonian in the A-reduction with an I r representation, rovibrational constants, including all five quartic terms for both ground state and upper state, were obtained with greater accuracy than those derived by Tan and Lebron [4]. Additionally, the equilibrium state rovibrational constants of C 2 HD 3 were calculated for the first time using B3LYP/cc-pVTZ, MP2/cc-pVTZ and CCSD(T)/cc-pVTZ levels of theory, and their values were compared to the ground state constants derived using ground state combination differences (GSCDs) from the assigned infrared transitions.…”

“…This interest has since led to studies being carried out on the vibrational and rovibrational structures of the isotopologue ethylene-d 3 (C 2 HD 3 ), by low-resolution [1][2][3] and high-resolution [4] infrared spectroscopies.…”

“…The rovibrational structure of the  8 band of C 2 HD 3 was studied for the first time in 2011 by Tan and Lebron [4] using a Fourier transform infrared (FTIR) spectrometer with a resolution of 0.0063 cm -1 . In their work, the C 2 HD 3 samples used were actually present as a 2% trace impurity in a C 2 D 4 gas sample.…”