The hydrogen-transfer reaction of HC≡CF→C=H(F) was taken as an example to calculate the microcanonical unimolecular rate constants with consideration of the tunneling correction and the curvature correction and the selection of the rotation states. The results indicate that the tunneling and the curvature increase much obviously the reaction rate constants in the lower energy regions than in the heigher regions. The rate constants in A' and A" symmetry, k~A'(E) and k~A"(E) respectively, have also been studied. The calculations show that k~A'(E) is larger than k~A"(E), and that the two constants tend to consistent with the increase in enrgy.

Key words: REACTION RATE CONSTANT, TUNNELING EFFECT, CURVATURE, MICROCANOMICAL ENSEMBLE