The first topic is development of efficient methods for locating paths that connect local minima on potential energy surfaces, using only knowledge of the reactant and product coordinates.  A recent development of this type, the Freezing String Method (FSM) will be discussed in detail, and contrasted with the earlier Growing String Method (GSM), in terms of both formal properties, and numbers of gradients typically required.  Either an FSM or GSM calculation yields a high quality guess at a transition structure, which can be refined by local optimization methods.  The talk will finish with discussion of the quasiclassical trajectory (QCT) method to characterize barrier crossing and recrossing dynamics.  For catalytic systems, with metastable intermediates separating reactants from products, short trajectories launched from transition states can yield product distributions that cannot be learned from the reaction path alone.  This will be illustrated with hydrocarbon cracking reactions in zeolites.

Efficient methods for locating transition structures and exploring the dynamics associated with barrier crossing

244th National Meeting (2012)

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