Speaker
Description
In this paper, we present computations of the optical absorption spectra of T graphene quantum dots (TGQD) employing a π-electron method and long-range Coulomb interactions within the Pariser-Parr-Pople (PPP) model Hamiltonian [1]{2]. The Configuration-Interaction (CI)[3][4] approach is used at various levels to incorporate electron-correlation effects on the ground and excited states. The method is thoroughly benchmarked by calculating the linear optical absorption spectra of several types of TGQDs. The outcomes are in good agreement with those attained by First-principles calculations. We investigated the influence of TGQDs' size and shape on their optical properties. The symmetry of the TGQDs is explored to identify allowed dipole transitions. It was revealed that HOMO to LUMO transition is dipole forbidden, suggesting that the optical and electronic band gaps of these TGQDs are different. Absorption maxima of these TGQDs are observed in UV to visible regions of light. Overall, our theoretical approach describes the linear optical characteristics of T-graphene quantum dots, which may offer helpful information for experimental characterization of these materials.
REFERENCES
[1]. J. A. Pople, Trans. Faraday Soc. 49, 1375 (1953).
[2]. R. Pariser and R. G. Parr, J. Chem. Phys. 21, 767 (1953).
[3]. A. Shukla, Phys. Rev. B 65, 125204 (2002).
[4]. A. Shukla, Phys. Rev. B 69, 165218 (2004).
