THE ROTATIONALLY RESOLVED INFRARED-SPECTRUM OF THE NU(1) STRETCH OF THE ALLYL RADICAL

Transient infrared (IR) laser spectroscopy near 3100 cm(-1) was used t o observe the v(1) and v(13) transitions of the allyl radical, with th eir band origins found to lie at 3113.9779(3) cm(-1) and near 3110.5 c m(-1), respectively. Detailed assignment and analysis of the v(1) tran sition identified over 1100 transitions, and yielded improved values f or Delta(K) and Phi(K) ground state centrifugal distortion constants, as well as a new set of excited state (v(1) = 1) rotational and centri fugal distortion constants, in addition to determining the band origin . Transitions involving states with quantum number up to K-a = 11 and N = 27 were identified. Strong perturbations were found in the excited state, included global perturbations of the K-a' = 3 branch, extensiv e perturbations in the K-a' =2 and 4 branches, and very localized pert urbations in the K-a' = 6 branch. The K-a' = 9 and 10 branches also ap pear to be significantly perturbed. Possible sources for these perturb ations are discussed. (C) 1998 American Institute of Physics. [S0021-9 606(98)01242-2].