Fig. 2.

Stable superoxo species. (A and B) Calculations of the coadsorption of $\pi$ and $\tau$ molecules (A) and $\omega$ and $\pi$ molecules (B) to the slab with one ${\mathrm{V}}_{\mathrm{O}}$. In A and B, Insets in the calculated DOS magnify the unoccupied in-gap states residing on the adsorbed molecules, and the partial-charge-density plots show the spatial distribution of these unoccupied in-gap states. (C) Table summarizing the adsorption energy per molecule $E_{\mathrm{a}\mathrm{d}\mathrm{s}}$, the bond length $d$(${\mathrm{O}}_2$), Bader charge $Q_{\mathrm{B}}$, and the spin state of each molecule in the coadsorption calculations.