First-principles calculations of the structural, electronic, vibrational and magnetic properties of C_{60} and C_{48}N_{12}: a comparative study

Abstract

In this work, we perform first-principles calculations of the structural, electronic, vibrational and magnetic properties of a novel ${\mathrm{C}}_{48}{\mathrm{N}}_{12}$ azafullerene. Full geometrical optimization shows that ${\mathrm{C}}_{48}{\mathrm{N}}_{12}$ is characterized by several distinguishing features: only one nitrogen atom per pentagon, two nitrogen atoms preferentially sitting in one hexagon, ${\mathrm{S}}_6$ symmetry, 6 unique nitrogen-carbon and 9 unique carbon-carbon bond lengths. The highest occupied molecular orbital of ${\mathrm{C}}_{48}{\mathrm{N}}_{12}$ is a doubly degenerate level of $a_g$ symmetry and its lowest unoccupied molecular orbital is a nondegenerate level of $a_u$ symmetry. Vibrational frequency analysis predicts that ${\mathrm{C}}_{48}{\mathrm{N}}_{12}$ has in total 116 vibrational modes: 58 infrared-active and 58 Raman-active modes. ${\mathrm{C}}_{48}{\mathrm{N}}_{12}$ is also characterized by 8 ${}^{13}\mathrm{C}$ and 2 ${}^{15}\mathrm{N}$ NMR spectral signals. Compared to ${\mathrm{C}}_{60}$, ${\mathrm{C}}_{48}{\mathrm{N}}_{12}$ shows an enhanced third-order optical nonlinearities which implies potential applications in optical limiting and photonics.

a long version of our manuscript submitted to J.Chem.Phys