Raman scattering in C_{60} and C_{48}N_{12} aza-fullerene: First-principles study

摘要

We carry out large scale {\sl ab initio} calculations of Raman scatteringactivities and Raman-active frequencies (RAFs) in ${\rm C}_{48}{\rm N}_{12}$aza-fullerene. The results are compared with those of ${\rm C}_{60}$.Twenty-nine non-degenerate polarized and 29 doubly-degenerate unpolarized RAFsare predicted for ${\rm C}_{48}{\rm N}_{12}$. The RAF of the strongest Ramansignal in the low- and high-frequency regions and the lowest and highest RAFsfor ${\rm C}_{48}{\rm N}_{12}$ are almost the same as those of ${\rm C}_{60}$.The study of ${\rm C}_{60}$ reveals the importance of electron correlations andthe choice of basis sets in the {\sl ab initio} calculations. Our bestcalculated results for ${\rm C}_{60}$ with the B3LYP hybrid density functionaltheory are in excellent agreement with experiment and demonstrate the desirableefficiency and accuracy of this theory for obtaining quantitative informationon the vibrational properties of these molecules.