Gradient line reaction paths for hindered internal rotation in H2BNH2 and inversion in PF3

The potential energy surfaces of H 2 NBH 2 and PF 3 in the regions of the hindered internal rotation in aminoborane and the inversion in trifluorophosphine have been studied in terms of the gradient line (steepest-descent) reaction pathways. We find that the gradient line reaction path for the aminoborane internal rotation consists of two equivalent paths separated in configuration space; the gradient line reaction path for the PF 3 inversion consists of three equivalent reaction paths. Hence, the aminoborane internal rotation and the AF 3 (A = P, S + , Sb, As, Bi) inversion are fundamentally multidimensional processes.