Structure and property study of the O2 + O2− electron transfer system

Abstract

The structures and the properties of the O 2 + O − 2 electron transfer system are studied with ab initio calculations at the UMP2(full)/6–311 + G ∗ basis set level for the five selected structures: two T-type, collinear, parallel, and crossing. The stability of the encounter complex, O 2···O − 2, in the five encounter structures is compared for the low (doublet) and the high (quartet) spin states. The activation barriers and the coupling matrix elements in the electron transfer process are also calculated for two different spin states. Results indicates that the interaction between the donor and the acceptor in the encounter complexes is weak and the structures are floppy. Although the encounter complexes in doublet states have lower activation barriers and greater coupling matrix elements than those in quartet state, the low spin coupling needs the change of spin state of an electron in the species O 2 and will result in the negative stabilization energies for the encounter complexes. The electron transfer is more likely to take place via the quartet state.