The binding energies of CH3, CH3 + H, CH2, and CH to (5, 5), (9, 0), and (10, 0) carbon nanotubes are determined computationally. The binding energy of a single CH3 is very small because only one adsorbate-tube bond is formed for the loss of one tube pi bond. For CH3 + H, CH2 and CH the binding energies are much larger since two adsorbate-tube bonds form for the loss of one tube pi bond. For CH2 and CH, which bond with two different tube atoms, for some orientations a strong bonding with the tube occurs that results in the breaking of a tube C-C bond. The calculated IR spectra show that the C-H stretching and H-C-H bending regions offer the possibility of observing these species. (c) 2007 Elsevier B.V. All rights reserved.