2-DIMENSIONAL POTENTIAL-ENERGY SURFACES FOR I)-2(X(1)SIGMA(G)(+))-]HCN(X(1)SIGMA(+))+N(S-4)(N)

Two-dimensional potential energy surfaces for the CH+N-2-->HCN+N(S-4) reaction are obtained which describe (i) the C-2 nu HCN2 region of the doublet potential energy surface; (ii) the region of the quartet pote ntial energy surface including the C-2 nu minimum and the dissociation pathway to HCN+N(4S); and (iii) the region of crossing of the doubler and quarter surfaces. These surfaces are fit using simple, physically motivated functional forms. In the first and third regions, the activ e coordinates are the C-N-2 [center-of-mass (c.m.)] distance and the N -N distance. In the second region, the active coordinates are the C-N' separation, where N' denotes the departing N atom, and the angle H-C- N. In the following paper, this potential is used to study the dynamic s of the title reaction and to compute Boltzmann rate constants.