Priyanka Pandey


Pandey P., Naik S., Keshavamurthy S.
The presence of higher-index saddles on a multidimensional potential energy surface is usually assumed to be of little significance in chemical reaction dynamics. Such a viewpoint requires careful reconsideration, thanks to elegant experiments and novel theoretical approaches that have come about in recent years. In this work, we perform a detailed classical and quantum dynamical study of a model two-degree-of-freedom Hamiltonian, which captures the essence of the debate regarding the dominance of a concerted or a stepwise reaction mechanism. We show that the ultrafast shift of the mechanism from a concerted to a stepwise one is essentially a classical dynamical effect. In addition, due to the classical phase space being a mixture of regular and chaotic dynamics, it is possible to have a rich variety of dynamical behavior, including a Murrell – Laidler type mechanism, even at energies sufficiently above that of the index-2 saddle. We rationalize the dynamical results using an explicit construction of the classical invariant manifolds in the phase space.
Keywords: reaction mechanisms, index-2 saddles, classical-quantum correspondence, dynamic Murrell-Laidler, invariant manifolds, concerted and sequential reactions
Citation: Pandey P., Naik S., Keshavamurthy S.,  Classical and Quantum Dynamical Manifestations of Index-2 Saddles: Concerted Versus Sequential Reaction Mechanisms, Regular and Chaotic Dynamics, 2021, vol. 26, no. 2, pp. 165-182

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