Fourier transform infrared spectroscopy of D212CO in the 2500-4500 cm-1 region and the first rovibrational analysis of its v2=2 state

A low-resolution (0.5 cm(-1)) Fourier transform infrared (FTIR) spectrum of formaldehyde-d(2) ((D2CO)-C-12) in the 2500-4500 cm(-1) region was recorded to study the combination bands in this region. The bands v(2) + v(4), v(2) + v(6), v(2) + v(3), v(1) + v(2,) v(2) + v(5), 3v(3), 2v(2) and 2v(5) were identified and their band centers (with an uncertainty of +/- 0.1 cm(-1)) and band types were determined. Furthermore, the high-resolution FTIR spectrum of the 2v2 overtone band (3315-3440 cm(-1)) of (D2CO)-C-12 was recorded at an unapodized resolution of 0.0063 cm(-1) and its infrared lines were analyzed. A total of 970 rovibrational transitions have been assigned and fitted up to J' = 35 and K-a = 14 using the Watson's A-reduced Hamiltonian in the I-r representation. Upper state (v(2) = 2) rovibrational constants inclusive of three rotational and five quartic centrifugal distortion constants were accurately determined for the first time. The band center of the 2v(2) band was determined as 3385.200666 +/- 0.000035 cm(-1). The rms deviation of the rovibrational fit was 0.00093 cm(-1). From the fitting of 451 ground state combination differences (GSCDs) of (D2CO)-C-12 which were derived from the infrared transitions of the 2v(2) band of this work, together with 360 microwave frequencies from a previous study, new and accurate ground state constants of (D2CO)-C-12 up to three octic terms were obtained. The combination and overtone bands and the newly assigned high-resolution infrared lines of the 2v(2) band in the 2500-4500 cm(-1) region can be used to detect (D2CO)-C-12 in this infrared region. In addition, the results derived from this study give information on the rovibrational molecular structure of (D2CO)-C-12. (C) 2017 Elsevier Inc. All rights reserved.