O-2 diffusion in SiO2: Triplet versus singlet - art. no. 155901

We address the diffusion of the oxygen molecule in SiO2, using first-princi ples spin-polarized total-energy calculations. We find that the potential e nergy surfaces for the singlet and triplet states are very different in cer tain regions, and that the O-2 molecule preserves its spin-triplet ground s tate not only at its most stable interstitial position inside the solid but also throughout its diffusion pathway. Therefore, the singlet state is not a good approximation to describe the behavior Of O-2 inside SiO2, and spin -polarization effects are fundamental to understand the properties of this system.