Geometry and electronic structure of neutral and charged B21 clusters

We use random searches, basin hopping and simulated annealing techniques to obtain low energy isomers of the B21 cluster. Our search shows that planar structures dominate the low energy isomers of B21 for the neutral as well as singly positively and negatively charged states continuing the trend seen for smaller clusters. The ring-like structures previously reported as global minima for the B20 and B21 are about 1 eV higher than the most stable planar isomer. The quantum chemical calculations using the second order Moller–Plasset perturbation theory agree with the DFT predictions.