High-resolution infrared spectra of jet-cooled allyl radical (CH2–CH–CH2): ν2, ν3, and ν14 C–H stretch vibrations

Abstract

The high-resolution infrared spectrum of jet-cooled allyl radical (CH2–CH–CH2) in the region 3010–3045 cm−1 has been recorded in pulsed slit jet expansions using both modulated discharge and excimer laser flash photolysis methods to produce the radicals. Over 400 transitions are observed and assigned to the ν2, ν3, and ν14 C–H stretch vibrations. The band origins have been determined to be 3033.8745(6), 3023.4605(6), and 3020.32(1) cm−1, respectively. Spectral analysis indicates that all three upper states are perturbed, with the perturbations in the ν14 upper state so pervasive as to make least-squares analysis difficult. The gas phase frequencies reveal a somewhat unusual, in comparison with the other bands, matrix shift to the blue for ν2 of 18 cm−1.