Fig. 5

Geometrically optimized configurations of some atomic clusters in g-As-Se computed by ab initio quantum chemical modeling with RHF/6-311G^* basis set [39]. a AsSe_3/2 pyramid (two of three Se atoms contribute with their BFSA to one hemisphere). b As₂Se_4/2 bridge (all four Se atoms contribute with their BFSA to one hemisphere)