10 μm High-Resolution Spectra of Acrolein (trans-form)

Acrolein (CH 2 CHCHO) is one of the four (in addition to methanol CH 3 OH, Ac- etaldehyde CH 3 CHO, and 1,3-butadiene CH 2 CHCHCH 2 ) 2004 target molecules from main- and side-stream (MS and SS) cigarette smoke 1 . The present work is aimed at extending the database of high resolution laboratory spectroscopic information on the molecule in the 10 μm region. We have obtained 10 μm high resolution spectra from NRC both at room and cooled temperatures at 0.002 cm ^-1 resolution. The spectra cover several vibrational bands including the two dominant ones, the ν16 CH 2 out-of-plane rocking and ν14 CH2 twisting. Analyses of the ν16 and ν14 bands are now at advanced stages. More specifically, about 1085 lines have been assigned to the ν16 band for transitions to upper state K 0 a = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10, and about 800 lines have assigned to the ν14 band for transitions to upper state K 0 a = 1, 2, 3, 4, 5, 6, 7 and 8. We have applied an isolated band model to each band using Maki's asymmetric rotor Hamiltonian in which some assigned transitions were removed from our fits. In our analysis, we have encountered challenges due to high line density as well as perturbations. For the latter, J reduced upper state term values have been obtained and plotted as a function of J, indicating possible interactions among the two states. For intensity information, we have carried out ab initio dipole derivative calculations using the procedure explained in Ref. [2] 2 for 1,3-butadiene. A line list with position and intensity has been compiled using this ab initio dipole derivative and the rotational constants obtained from the present work