Anchoring the potential energy surface for the

Authors: Meiling Zhang Yanjun Hao Yundong Guo Yaoming Xie Henry F Schaefer

Publish Date: 2016

Volume: , Issue: , Pages: 177-185

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Abstract

The forward and reverse reactions Br + H2O → HBr + OH are important in atmospheric and environmental chemistry Five stationary points on the potential energy surface for the Br + H2O → HBr + OH reaction including the entrance complex transition state and exit complex have been studied using the CCSDT method with correlationconsistent basis sets up to ccpV5ZPP Contrary to the valence isoelectronic F + H2O system the Br + H2O reaction is endothermic by 318 kcal/mol after zeropoint vibrational relativistic and spin–orbit corrections consistent with the experimental reaction enthalpy The CCSDT/ccpV5ZPP method predicts that the reverse reaction HBr + HO → Br + H2O has a complex but no classical barrier When zeropoint vibrational energies are added the transition state lies 025 kcal/mol above the separated products This is consistent with the negative temperature dependence for the rate constant observed in experiments The entrance complex is predicted to lie 26 kcal/mol below separated Br + H2O The exit complex is predicted to lie 18 kcal/mol below separated HBr + OH

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