Abstract
We present an ab initio molecular-dynamics study of III-V hydrogenated microclusters with the purpose of identifying stable and optically active structures suitable for inclusion in zeolite cages. We find that the most stable and optically active clusters are distorted tetrahedral structures with a majority of atoms of group V. Cubic clusters show unexpected structural stability, but with negligible matrix element for optical transitions close to the energy gap. Our results are compatible with existing experimental data.