Geometry, electronic structure, and optical properties of boron cages: a first-principles DFT study

A systematic study of the structural, electronic, and optical properties of cage-like boron clusters, with the number of constituent atoms ranging from 20 to 122, has been carried out within the framework of density-functional theory (DFT), employing the 6-31G(d,p) extended basis set. The dynamic stability of the clusters is analyzed through vibrational frequency analysis, while to study the thermodynamic stability, we computed their binding energies per atom. The results suggest that the 32- and 92-atom cages are the most stable among the small and the large structures, and their stability is analyzed. The optical absorption spectra of these cages are computed using time-dependent density-functional theory (TDDFT), which suggests their applications in optoelectronic devices in a wide range of the spectrum.