Calculation of hydrogen abstraction reaction on hydrogen-covered H/C(1 1 1) diamond surface abstracted by non-hydrocarbon species

In the present study, the energetics of H-abstraction reaction on the hydrogen-covered diamond H/C(111) surface abstracted by hydrogen atom (H), carbon (CH₃, C₂H), nitrogen (NH₂, CN), oxygen (O, OH), and halogen-containing radicals (F, Cl, Br, CF₃, CCl₃) in gas phase in the diamond chemical vapor deposition process were examined using ab initio calculation. The calculations for O, F, Cl, and Br radicals gave results consistent with available experimental results. These calculated results show that F, Cl, O, OH, CN, and C₂H are much stronger abstractors while NH₂, CH₃, CF₃, and CCl₃ radicals are weaker abstractors, compared with this abstraction reaction abstracted by H atoms, which is in excess in gas phase. Finally, the energy barrier heights of these examined radicals are generally correlated well with an index of electrophilicity, suggesting that this index serves as a good index to account for the ability of these examined radicals to abstract the adsorbed H atoms on H/C(111) diamond surface.