A generalized log-derivative method for the treatment of asymmetric collinear reactions in hyperspherical coordinates

The log-derivative method is applied to the treatment of collinear reactions using hyperspherical coordinates. As a test example the asymmetric reaction F + H₂ → FH + H on the Muckerman V potential surface is chosen. Extensive investigations of the convergence properties of the new “L-matrix propagation” program are carried out and it is shown that this is an accurate and efficient code for solving the (hyper)-radial coupled equations. Much attention is paid to a proper and effective treatment of some strong nonadiabatic effects occurring in asymmetric reactions. The curve crossing approximation is applied and its adequacy is demonstrated by comparison of the scattering matrices with the results obtained in the natural reaction coordinates approach. Modified versions of the two standard programs, the RXN1D and the S-matrix propagation program, were exploited in the performed tests.