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