Absorption spectrum of small nanodiamonds, i.e., diamondoids has been recently measured exhibiting features that are not understood. Previous calculations, even beyond standard density-functional theory (DFT), failed to obtain the experimental optical gaps (Eg) of diamondoids. We show that all-electron time-dependent DFT (TD-DFT) calculations including hybrid functional in the TD-DFT kernel are able to provide quantitatively accurate results. Our calculations demonstrate that Rydberg transitions are characteristic even for relatively large nanodiamonds resulting in low Eg. The nonmonotonic size dependence of Eg is explained by symmetry considerations.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - Oct 23 2009|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics