Interaction of ethane with singlet oxygen: A theoretical study of potential energy surfaces

A study of the C2H6+O2 reaction system was carried out using ab initio quantum chemistry methods. The main reaction and quenching channels were identified, corresponding activation energies were calculated, and the pathways of the minimum reaction energy were constructed. It was found that the reaction channels of ethane molecule with singlet delta oxygen proceed with a lower barrier than with the oxygen molecule in the ground state. The reaction of ethane with singlet sigma oxygen, in turn, proceeds through the dissociation of the O2 molecule; however, the quenching channel is still possible because of the intersystem crossings. Based on the obtained data, the appropriate reactions rate constants can be estimated by using variational and nonadiabatic transition state theories.