A quantum mechanical approach to the kinetics of the hydrogen abstraction reaction H 2 O 2 + • OH → HO 2 + H 2 O

The kinetics of the hydrogen abstraction from H 2 O 2 by • OH has been modeled with MP2/6‐31G*//MP2/6‐31G*, MP2‐SAC//MP2/6‐31G*, MP2/6‐31+G**//MP2/6‐31+G**, MP2‐SAC// MP2/6‐31+G**, MP4(SDTQ)/6‐311G**//MP2/6‐31G*, CCSD(T)/6‐31G*//CCSD(T)/6‐31G*, CCSD(T)/6‐31G**//CCSD(T)/6‐31G**, CCSD(T)/6‐311++G**//MP2/6‐31G* in the gas phase. MD simulations have been used to generate initial geometries for the stationary points along the potential energy surface for hydrogen abstraction from H 2 O 2 . The effective fragment potential (EFP) has been used to optimize the relevant structures in solution. Furthermore, the IEFPCM model has been used for the supermolecules generated via MD calculations. IEFPCM/MP2/6‐31G* and IEFPCM/CCSD(T)/6‐31G* calculations have also been performed for structures without explicit water molecules. Experimentally, the rate constant for hydrogen abstraction by • OH drops from 1.75 × 10 −12 cm 3 molecule −1 s −1 in the gas phase to 4.48 × 10 −14 cm 3 molecule −1 s −1 in solution. The same trend has been reproduced best with MP4 (SDTQ)/6‐311G**//MP2/6‐31G* in the gas phase (0.415 × 10 −12 cm 3 molecule −1 s −1 ) and with EFP (UHF/6‐31G*) in solution (3.23 × 10 −14 cm 3 molecule −1 s −1 ). © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 502–514, 2005