Two-dimensional potential energy surfaces for CH(X²Π)H-N ₂(X ¹Σ_g⁺) →HCN(X ¹Σ⁺)+N(⁴S)

Two-dimensional potential energy surfaces for the CH+N₂→ HCN+N(⁴S) reaction are obtained which describe (i) the C_2v HCN₂ region of the doublet potential energy surface; (ii) the region of the quartet potential energy surface including the C_2v minimum and the dissociation pathway to HCN+N(⁴S); and (iii) the region of crossing of the doublet and quartet surfaces. These surfaces are fit using simple, physically motivated functional forms. In the first and third regions, the active coordinates are the C-N₂ [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 dynamics of the title reaction and to compute Boltzmann rate constants.