alpha-halobenzyl radicals, such as C6H5CHCl, C6H5CHBr, and C6H5CCl2, along with C6H5CH2, are generated by pyrolysis and photolysis methods. The mechanism of the formation of the alpha-halobenzyl radicals in a pyrolysis nozzle is analyzed. Secondary reactions play an important role in the pyrolysis process. Spectra of these supersonic jet cooled radicals are detected by laser induced fluorescence and multiphoton ionization techniques in the 21 200-23 500 cm(-1) range. Assignment of important vibronic bands of the alpha-halobenzyl radicals is made by comparing their spectra to that of the benzyl radical and by employing rotational contour and vibrational mode analyses and ab initio calculations. The similarity between the vibronic structure of the benzyl radical and alpha-halobenzyl radicals suggests a similar vibronic coupling scheme for them. Substitution of halogen atoms on the methylene group of the benzyl radical has only a modest affect on the vibronic transitions studied. (C) 1997 American Institute of Physics.