Vibrational stability and electronic structure of a ${\text{B}}_{80}$ fullerene

We investigate the vibrational stability and the electronic structure of the proposed icosahedral fullerenelike cage structure of ${\text{B}}_{80}$ [N. G. Szwacki, A. Sadrzadeh, and B. I. Yakobson, Phys. Rev. Lett. 98, 166804 (2007)], by an all electron density-functional theory using polarized Gaussian basis functions containing 41 basis functions per atom. The vibrational analysis of ${\text{B}}_{80}$ indicates that the icosahedral structure is vibrationally unstable with seven imaginary frequencies. The equilibrium structure has $T_h$ symmetry and a smaller gap of 0.96 eV between the highest occupied and the lowest unoccupied molecular orbital energy levels compared to the icosahedral structure. The static dipole polarizability of a ${\text{B}}_{80}$ cage is $149{\text{Å}}^3$, and the first ionization energy is 6.4 eV. The ${\text{B}}_{80}$ cage has rather large electron affinity of 3 eV making it a useful candidate as electron acceptor if it is synthesized. The infrared and Raman spectra of the highly symmetric structure are characterized by a few absorption peaks.

Figure 1

(Color online) Optimized geometry of a ${\text{B}}_{80}$ cage.

Figure 2

(Color online) Unstable vibrational modes of an icosahedral ${\text{B}}_{80}$ cage.

Figure 3

(Color online) The orbital densities of the HOMO (left) and LUMO (right) of the ${\text{B}}_{80}$ cluster.

Figure 4

The vibrational density of states, infrared absorption intensity and the Raman scattering intensities of the ${\text{B}}_{80}$ cluster with $T_h$ structure.