The absorption of diamondoids from time-dependent density functional calculations

Márton Vörös, Tamás Demjén, A. Gali

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Diamondoids are small diamond nanocrystals with perfect hydrogenated surfaces. Recent absorption measurements showed that the spectrum of diamondoids exhibit features that are not understood from the theoretical point of view, e.g. optical gaps are only slightly larger than the gap of bulk diamond which runs against the quantum confinement effect. Previous calculations, even beyond standard density functional theory (DFT), failed to obtain the experimental optical gaps (E g) of diamondoids. We show that all-electron time-dependent DFT (TD-DFT) calculations including the PBEO hybrid functional in the TD-DFT kernel are able to provide quantitatively accurate results. Our calculations demonstrate that Rydberg transitions govern the low energy part of the absorption spectrum, even for relatively large nanodiamonds resulting in low E g. Since the optical gap of these diamondoids lies in the ultraviolet spectral region, we investigated whether simple adsorbates of the surface are able to shift the gap towards the infrared region. We found that a double bonded sulfur atom at the surface results in a substantial gap reduction.

Original languageEnglish
Title of host publicationMaterials Research Society Symposium Proceedings
Pages23-28
Number of pages6
Volume1370
DOIs
Publication statusPublished - 2011
Event2011 MRS Spring Meeting - San Francisco, CA, United States
Duration: Apr 25 2011Apr 29 2011

Other

Other2011 MRS Spring Meeting
CountryUnited States
CitySan Francisco, CA
Period4/25/114/29/11

Fingerprint

Density functional theory
Diamond
Diamonds
Nanodiamonds
Quantum confinement
Adsorbates
Electron transitions
Sulfur
Discrete Fourier transforms
Nanocrystals
Absorption spectra
Infrared radiation
diamonds
Atoms
density functional theory
Electrons
nanocrystals
sulfur
absorption spectra
shift

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering
  • Mechanics of Materials

Cite this

Vörös, M., Demjén, T., & Gali, A. (2011). The absorption of diamondoids from time-dependent density functional calculations. In Materials Research Society Symposium Proceedings (Vol. 1370, pp. 23-28) https://doi.org/10.1557/opl.2011.893

The absorption of diamondoids from time-dependent density functional calculations. / Vörös, Márton; Demjén, Tamás; Gali, A.

Materials Research Society Symposium Proceedings. Vol. 1370 2011. p. 23-28.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Vörös, M, Demjén, T & Gali, A 2011, The absorption of diamondoids from time-dependent density functional calculations. in Materials Research Society Symposium Proceedings. vol. 1370, pp. 23-28, 2011 MRS Spring Meeting, San Francisco, CA, United States, 4/25/11. https://doi.org/10.1557/opl.2011.893
Vörös M, Demjén T, Gali A. The absorption of diamondoids from time-dependent density functional calculations. In Materials Research Society Symposium Proceedings. Vol. 1370. 2011. p. 23-28 https://doi.org/10.1557/opl.2011.893
Vörös, Márton ; Demjén, Tamás ; Gali, A. / The absorption of diamondoids from time-dependent density functional calculations. Materials Research Society Symposium Proceedings. Vol. 1370 2011. pp. 23-28
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