Detailed calculations were made of the chemical interaction of molecular and atomic H with a single monovacancy or divacancy in a (12,0) nanotube, within the framework of a tight-binding potential model. In the case of a monovacancy, the dangling bond in the defect supplied a large cross-section for the capture of either a H molecule or an atomic H nearby. The dangling bond site could be hydrogenated in either an sp2-like or sp3-like hybridization. The energetic calculations demonstrated that the void in a monovacancy was not an effective access point for the penetration of either atomic or molecular H between the outer and inner sides of the tube wall; but it could be in a divacancy.Interaction of Hydrogen with Vacancies in a (12,0) Carbon Nanotube. A.J.Lu, B.C.Pan: Physical Review B, 2005, 71[16], 165416 (6pp)