An efficient method was recently introduced by Thompson and Miller [J. Chem. Phys. 106, 142 (1997)] for calculating thermal rate constants using the flux-flux autocorrelation function with absorbing boundary conditions. The method uses an iterative method to exploit the low rank feature of the Boltzmannized flux operator and subsequently only propagates the eigenvectors that have significant contributions to the rate constant. In the present article, this method is used to calculate the thermal rate constants of the Cl+H-2-->HCl+H reaction in the temperature range of 200-1500 degrees K. Total angular momentum is treated by employing the body-fixed axis frame, both exactly and also via various approximations. Comparisons with previous exact and approximate theoretical results are made. (C) 1997 American Institute of Physics.