An efficient algorithm for the approximate location of transition structures in a diabatic surface formalism

Abstract

An efficient algorithm is presented for the approximate location of a transition structure by finding the minimum of the seam of intersection of two diabatic surfaces. The algorithm is sufficiently stable that the optimization can be started from the product geometry. The procedure is illustrated with two examples. The approximate structures obtained are sufficiently close to the corresponding MC SCF optimized structures, that the subsequent MC SCF gradient optimizations, starting from these points, converge easily.