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

COBOS, C. J.; MARIA EUGENIA TUCCERI; BADENES, M. P.

JOURNAL OF PHYSICAL CHEMISTRY A

AMER CHEMICAL SOC

Lugar: Washington; Año: 2016

1089-5639

The kinetics of the gas phase recombination reaction HO + HO2 + He → HOOOH + He has been studied between 200 and 600 K by using the SACM/CT model and the unimolecular rate theory. The molecular properties of HOOOH were derived at the CCSD(T)/aug-cc-pVTZ ab initio level of theory, while relevant potential energy features of the reaction were calculatedat the CCSD(T)/aug-cc-pVTZ//CCSD(T)/aug-cc-pVDZ level. The resulting high and low pressure limit rate coefficients are k∞ = 3.55 x 10-12 T/300)0.20 cm3 molecule-1 s-1 and k0 =[He] 1.55 x 10-31 (T/300)-3.2 cm3 molecule-1 s-1. The rate coefficients calculated over the 6 x10-4 ? 400 bar range are smaller at least in a factor of about 60 than the consensus value determined for the main reaction channel HO + HO2 → H2O + O2, indicating that the recombination pathway is irrelevant.