Heather Abbott-Lyon - Microcanonical transition state theory for gas-surface reaction dynamics

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      Publication Details (including relevant citation   information):

      H.L. Abbott and I. Harrison, Journal of   Physical Chemistry A., 111, 9871 (2007)


      Microcanonical transition state theory incorporating quantized   surface vibrations is shown to be applicable to a benchmark   system for gas-surface reaction dynamics, the activated   dissociative chemisorption and associative desorption of hydrogen   on Cu(111). The local hot spot model, defining 3 transition state   parameters, predicts the diverse range of experimentally observed   dissociative sticking and quantum state resolved desorption   behavior and provides a statistical baseline for the gas-surface   reactivity against which dynamical effects can be identified.   Contrary to popular current notions, surface phonons are vital   participants in the hydrogen chemisorption dynamics whereas   molecular rotations are approximately spectator degrees of   freedom at thermally accessible energies (i.e., for Er less than   ~40 kJ/mol). The threshold energy for dissociative chemisorption   of H2 on Cu(111) is E0 = 62 kJ/mol. Dynamical effects are   identified that suggest the dissociative transition state is   slightly early rather than late. A versatile theoretical   framework capable of treating the dynamics of activated condensed   phase reactions is validated.

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