The 2CH excitation band in C_2H_2–N_2O and 2CH+torsion combination bands in C_2H_2–N_2O and C_2H_2–CO_2

摘要

A preliminary analysis of the 2CH excitation band in C_2H_2–N_2O in the 1.5 mm range (K. Didriche, C. Lauzin, P. Macko, M. Herman and W.J. Lafferty, Chem. Phys. Letters 469, 35 (2009).), only considering 117 low J-, and Ka- vibration-rotation lines, is significantly extended thanks to the analysis of new spectra including very regular series of lines with J/K_a up to 31/15. 1271 b-type lines were assigned. Perturbations are briefly discussed. The rotational temperature in the experiments is estimated to be 20K and the upper state mean half-time is 1.6ns for non perturbed levels. The previous analyses of the 2CH t torsion band in C2H2–N2O and in C2H2–CO2(C. Lauzin, K. Didriche, T. F?ldes and M. Herman, Mol. Phys. 109, 2105 (2011).), are also extended to include 286 and 234 lines, respectively, also correcting for calibration errors. New rotational constants are obtained using a rigid rotor Hamiltonian by simultaneously fitting the ground, 2CH and 2CH t torsion states in C_2H_2–N_2O, and the latter state, only, in C_2H_2–CO_2.