Characterization of the potential energy surface for CH 3+O 2→products

Abstract

Complete active space SCF/internally contracted configuration interaction calculations using large atomic natural orbital basis sets are reported for CH 3+O 2. Two potential energy surfaces are found to be important in the CH 3+O 2 reaction. In C s symmetry, the lower 2A″ surface correlates with CH 3+O 2( 3Σ − g) and connects to a bound CH 3OO species with no barrier, but leads only to CH 3O+O products. A higher surface of 2A′ symmetry correlates with CH 3+O 2( 1Δ − g and leads to CH 2+OH with a computed barrier of 13.7 kcal/mol (with respect to CH 3+O 2( 3Σ − g)). Even in lower symmetry, two surfaces are involved leading to a more complex model for this reaction than had been previously considered.