The Shima-Baer's method without a distortion potential is improved by introducing a new L2 translational basis set in which no adjustable parameters are involved, but only mol. constants of the reactive system are included. The rate of convergence of reaction probabilities with respect to the translational basis functions is faster than before due to the existence of highly decaying factors in the basis functions within the nonclassical regions. It is found from calculation results for collinear exchange reaction H + H2 ?H2 + H that the rate of convergence with respect to the translational basis functions is close to that with a distortion potential, and the amount of computer work is obviously saved.

Key words: WAVE FUNCTIONS, GREEN'S FUNCTION, REACTIVE SCATTERING