Single-site Ga 3+ -silica structures are developed starting from a recently reported amorphous silica slab model. The amorphous structure originates from an annealing procedure using molecular dynamics and continuous dehydration processes. The periodic model has a sufficiently large unit cell to incorporate the possibility of long-range reconstructions and interactions (Figure ). To create each single-atom Ga 3+ site, a Si atom in the amorphous model is replaced with Ga, and a proton is added to an adjacent oxygen atom to maintain a charge balance.