TOPOLOGICAL STUDIES ON IRC PATHS OF X-2-]XH+H REACTIONS(H)

Topological properties of potential energy and electronic density dist ribution on five reaction paths X + H-2 --> XH + H(X = H, N, HN, H2C, NC) are investigated at the level of UMP2/6-311G(d, p). It has been fo und that in the region of the reaction paths studied, where B(r(c))\(s ) > 0 [B(r(c))\(s) is the product of rho(r(c)) and del(2) rho(r(c)) at the point of reaction process, i.e., B(r(c))\(s) = rho(r(c))del(2) rh o(r(c))] is basically the same as the region of V ''(s) < 0 [V''(s) is the second derivative of potential energy with respect to the reactio n coordinate, i.e., V ''(s) = d(2)V/ds(2)], and the point with maximum B(r(c))\(s) is almost coincident with the point of minimum V ''(s). I t can be concluded from the calculated results that there is a good co rrelation between the topological properties of potential energy and e lectronic density distribution along the reaction path. The structure transition state of such collinear reactions may be determined by topo logical analysis of electronic density. (C) 1997 by John Wiley & Sons, Inc.