Role of the Recombination Channel in the Reaction between the HO and HO2 Radicals

M. E. TUCCERI; M. P. BADENES; C. J. COBOS

JOURNAL OF PHYSICAL CHEMISTRY A

AMER CHEMICAL SOC

Lugar: Washington; Año: 2017 vol. 121 p. 440 - 447

1089-5639

The kinetics of the gas phase recombination reactionHO + HO2 + He → HOOOH + He has been studied between 200and 600 K by using the SACM/CT model and the unimolecular ratetheory. The molecular properties of HOOOH were derived at theCCSD(T)/aug-cc-pVTZ ab initio level of theory, while relevantpotential energy features of the reaction were calculated at theCCSD(T)/aug-cc-pVTZ//CCSD(T)/aug-cc-pVDZ level. The resultinghigh and low pressure limit rate coefficients are k∞ = 3.55 ×10−12 (T/300)0.20 cm3 molecule−1 s−1 and k0 = [He] 1.55 × 10−31(T/300)−3.2 cm3 molecule−1 s−1. The rate coefficients calculatedover the 6 × 10−4 − 400 bar range are smaller at least in a factor ofabout 60 than the consensus value determined for the main reactionchannel HO + HO2 → H2O + O2, indicating that the recombinationpathway is irrelevant.