Electronic structure studies on neutral, singly and doubly charged ${\mathrm{Be}}_n$ clusters ($n\le 5$) have been carried out within the local spin-density formalism. We present results on their equilibrium geometries and atomization energies and discuss the stability of charged clusters. An extensive study of the Born-Oppenheimer surface of Be trimers is given and it is shown that small doubly charged clusters may exist in metastable states protected from dissociation by large energy barriers. The possibility of creating them by ocne- or two-step ionization processes criticalldepends on their geometries. We also address the issue of charge localization in doubly charged clusters.

• Received 20 May 1988

DOI:https://doi.org/10.1103/PhysRevLett.61.535