The potential energy surfaces for the ground and low-lying excited sta
tes of the H-3- system are calculated by means of the diatomics-in-mol
ecule (DIM) method. State-to-state reaction probabilities for rearrang
ement in H- + H-2, D2 collisions are calculated by the S matrix Kohn v
ariational method in the discrete variable representation for the coll
inear configuration, and the results for H- + D2 collisions compared w
ith recent experimental data.