The hydrogen abstraction reaction of 0 (P-3) with Si(2)Hb(6) has been studied theoretically for the first time. Two transition states of (3)A" and (3)A' symmetries have been located for this abstraction reaction. Geometries have been optimized at the MP2 level with 6-311G+(d) basis set. A modified G3MP2 method has been used for the final single-point energy calculation. Based on the ab initio data, the rate constants have been calculated over a wide temperature range of 200-3000 K using canonical variational transition state theory (CVT) with small curvature tunneling effect (SCT). The calculated CVT/SCT rate constants match well with the experimental value. (C) 2002 Elsevier Science B.V. All rights reserved.