Wobbe, M;
Zwijnenburg, M;
(2015)
Chemical trends in the optical properties of rocksalt nanoparticles.
Physical Chemistry Chemical Physics
, 2015
(17)
pp. 28892-28900.
10.1039/C5CP04851F.
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Abstract
The nature and magnitude of the optical gaps of rocksalt alkaline earth (MgO, CaO, SrO, MgS, MgSe) and transition metal chalcogenide (CdO, PbS) nanoparticles are studied using time-dependent density functional theory (TD-DFT) calculations on (MX)32 nanoparticles. We demonstrate, just as we previously showed for MgO, that TD-DFT calculations on rocksalt nanoparticles require the use of hybrid exchange–correlation (XC-)functionals with a high percentage of Hartree–Fock like exchange (e.g. BHLYP) or range-separated XC-functionals to circumvent problems related to the description of charge-transfer excitations. Concentrating on the results obtained with TD-BHLYP we show that the optical gap in rocksalt nanoparticles displays a wide range of behavior; ranging from large optical gaps stemming from a localized excitation involving corner atoms in alkaline earth oxides to a delocalized excitation and small optical gaps in the transition metal chalcogenides. Finally, we rationalize this wide range of behaviour in terms of differences in the degree to which the Coulombic interaction between the excited electron and hole is screened in the different nanoparticles, and relate it to the optical dielectric constants of the bulk materials the nanoparticles are made from.
Type: | Article |
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Title: | Chemical trends in the optical properties of rocksalt nanoparticles |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.1039/C5CP04851F |
Publisher version: | http://dx.doi.org/10.1039/C5CP04851F |
Language: | English |
Additional information: | Open Access Article. Published on 25 September 2015. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry |
URI: | https://discovery.ucl.ac.uk/id/eprint/1471686 |




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