Photoabsorption spectra of boron nitride fullerenelike structures

Abstract

Optical absorption spectra have been calculated for a series of boron nitride fullerenelike cage structures B n N n of sizes n = 12-36. The method used is a real-time, real-space implementation of the time-dependent density-functional theory, involving the full time propagation of the time-dependent Kohn-Sham equations. The spectra are found to be a possible tool for distinguishing between different boron nitride fullerene species and isomers. The trends and differences in the spectra are found to be related to the general geometry of the molecules. Comparison between local-density and generalized-gradient approximations for electron exchange-correlation functionals shows that both of them produce essentially the same spectral characteristics.

Optical Absorption Spectra of V+4 Isomers: One Example of First-Principles Theoretical Spectroscopy with Time-Dependent Density Functional Theory

“…In the case of free atoms, the energies for one-particle low-energy excitations agree with experiment to within 5-10 per cent [45]. For clusters of s-p metals, the errors in the position of the absorption peaks are usually in the 0.1-0.2 eV range [45,46,47], and the results are also very reasonable for carbon and BN clusters [48,49], and transition metal, organometallic, and molecular and van der Waals clusters [24,25,33,42], even in the high-energy range.…”

“…Although not entirely consistent, this is a common practice because the use of a better kernel does not significantly affect the results as long as the single-particle orbitals have been calculated with a suitable static v xc (r) potential [25]. This computational framework has been used successfully in the calculation of the optical spectra of atoms and clusters [24,25,33,42,43,44,45,46,47,48,49]. In the case of free atoms, the energies for one-particle low-energy excitations agree with experiment to within 5-10 per cent [45].…”

Electronic and atomic structure of the AlnHn+2 clusters

“…Although this procedure is not entirely consistent because the ground-state KS single-particle orbitals and energy eigenvalues correspond to a GGA functional, only adiabatic LDA kernels are currently implemented in OCTOPUS and other common TDDFT codes. In addition, Koponen et al 33 concluded that the LDA performs much better in the TDDFT, compared to static DFT. On the other hand, the most important requirement in obtaining a good photoabsorption spectrum is to have accurate single-particle energies and orbitals, obtained with a good static XC potential, 34,35 while the kernel is less important.…”

Single-Photon Emitters in Boron Nitride Nanococoons

“…Critically, the BNNC has facets consisting of many flat, stacked layers or walls of BN (see Figure 1) that possess a local crystal structure identical to 2D and 3D hBN. 18,19 This structure imparts a large bandgap, 20,21 as seen in other BN allotropes, and therefore permits the formation of deep-bandgap visible-range SPEs.…”