First analysis of the hybrid A/B-type 2v8 band of C2HD3 and the Coriolis interactions with the v3 + v4 band by high-resolution FTIR spectroscopy

Using a Fourier transform infrared (FTIR) spectrometer, the spectrum of the 2v(8) band of ethylene-d(3) (C2HD3) was measured between 1745 to 1905 cm(-1) at an unapodized resolution of 0.0063 cm(-1). For the first time, 1664 perturbed and unperturbed a- and b-type absorption lines of the band were recorded, assigned and fitted using the Watson's A-reduced Hamiltonian in the I-r representation to derive rovibrational constants up to four quartic terms for the v(8) = 2 state. Three rotational constants of the v(3) = v(4) = 1 state were also derived for the first time in this work from the analysis of the a- and b-Coriolis resonances with the v(8) = 2 state, together with a set of resonance parameters. The root-mean-square (rms) deviation of the FTIR fit was 0.0010 cm(-1). The band centers of the 2v(8) and v(3) + v(4) bands were determined to be 1831.457508 +/- 0.000071 cm(-1) and 1812.629 +/- 0.022 cm(-1), respectively. A set of ground state rovibrational constants of C2HD3 up to five quartic constants was also derived with improved precision from a simultaneous fit of 377 ground state combination differences (GSCDs) from a-type infrared transitions of the present analysis and 906 GSCDs from the previous work on the C-type v(8) band, with an rms deviation of 0.00043 cm(-1). The transition dipole moment ratio vertical bar mu(a/)mu(b vertical bar) was found to be 2.194 +/- 0.072. (C) 2017 Elsevier Inc. All rights reserved.