Analysis of the reaction and quenching channels in a H+O2(a1Δg) system

Comprehensive analysis based on quantum chemical calculations of potential energy surfaces of H+O-2(X-3 Sigma(-)(g)) and H+O-2(a(1)Delta(g)) systems has been carried out using the complete active space self-consistent field method for the doublet HO2(A ''), and quartet potential energy surfaces correlating with H+O-2(X-3 Sigma(-)(g)) and for the doublet HO2(A') one correlating with H+O-2(a(1)Delta(g)). The minimum energy paths were found and the values of energy for critical points were refined using the extended multi-configuration quasi-degenerate second order perturbation theory. Special attention was paid to the search for the intersystem crossing of doublet HO2(A') and quartet PESs. On the basis of these findings the probability of non-adiabatic quenching process O-2(a(1)Delta(g))+H -> O-2(X-3 Sigma(-)(g))+H was estimated. A critical evaluation of the energy barrier and rate coefficients for the O-2(a(1)Delta(g))+H reaction channel was conducted using of our own ab initio computations and those of other researchers, as well as experimental data. The temperature dependences of rate coefficients both for reaction and quenching channels are recommended on the base of quantum chemical analysis.