Theoretical studies of the stereodynamics for the exoergic reation O(¹D)＋HBr→OH＋Br have been carried out using the quasi-classical trajectory method on the ab initio global potential energy surface at three collision energies (20.90, 41.80 and 66.88 kJ/mol). The distribution P(θ_r) of angle between k and j shows that the rotational angular momentum polarization of the product molecule is quite strong and sensitive to increasing collision energy. The function which reflecting the angle distribution of three vectors correlation k-k -j indicates that j is not only aligned, but also oriented preferentially along the positive direction of the y-axis. With the increasing collision energy the orientation becomes weaker and weaker. There are two obvious distributions at (90°, 90°) and (90°, 270°) for the product rotational angular momentum , and the two distributions become intensive with the increase of collision energy, so the collision energy plays an important role in the distribution for the title reaction. The two distributions indicate that the product molecule is preferentially polarized perpendicular to scattering plane. In addition, the polarization dependent generalized differential cross-sections show the scattering direction of the product.

Key words: O(¹D)＋HBr, quasi-classical trajectory method, vector correlations, stereodynamics