Dynamics calculations require the construction of a potential energy surface (PES). This presentation will review a variety of PES construction techniques and illustrate their dynamics and kinetics implications for HO2, HOCO, and C2H5. For HO2 comparative studies of dissociation, isomerization, and IVR were carried out on three different PESs. Although qualitatively similar, these PESs produce qualitatively different dynamics. For HOCO, three different PESs produce very different tunneling rates as calculated by both POLYRATE and MultiWell. These rates can be distinguished by the experimental tunneling measurements of the Continetti group. For C2H5, an AIREBO molecular mechanics PES calibrated by electronic structure calculations at saddle points was used in propagating trajectories of 100 ps duration. Unlike short time trajectory studies on different PESs, these results see only RRKM-like unimolecular dissociation rates and provide no evidence of exceptionally long dissociation times (>1 ns) as measured by the Chen and Fischer groups.

Influence of potential energy surfaces on the reaction dynamics of small molecules

245th National Meeting (2013)

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