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Title: Intense fluorescence of Au 20

Abstract

Ligand-protected Au clusters are non-bleaching fluorescence markers in bio- and medical applications. We show that their fluorescence is an intrinsic property of the Au cluster itself. We find a very intense and sharp fluorescence peak located at λ =739.2 nm (1.68 eV) for Au20 clusters in a Ne matrix held at 6 K. The fluorescence reflects the HOMO-LUMO diabatic bandgap of the cluster. The cluster shows a very rich absorption fine structure reminiscent of well defined molecule-like quantum levels. These levels are resolved since Au20 has only one stable isomer (tetrahedral), therefore our sample is mono-disperse in cluster size and conformation. Density-functional theory (DFT) and time-dependent DFT calculations clarify the nature of optical absorptionand predict both main absorption peaks and intrinsic fluorescence in good agreement with experiment.

Authors:
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Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1378040
Report Number(s):
PNNL-SA-121242
Journal ID: ISSN 0021-9606; 49097; 49645; KP1704020
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 147; Journal Issue: 7; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; Environmental Molecular Sciences Laboratory

Citation Formats

Yu, Chongqi, Harbich, Wolfgang, Sementa, Luca, Ghiringhelli, Luca, Aprá, Edoardo, Stener, Mauro, Fortunelli, Alessandro, and Brune, Harald. Intense fluorescence of Au 20. United States: N. p., 2017. Web. doi:10.1063/1.4996687.
Yu, Chongqi, Harbich, Wolfgang, Sementa, Luca, Ghiringhelli, Luca, Aprá, Edoardo, Stener, Mauro, Fortunelli, Alessandro, & Brune, Harald. Intense fluorescence of Au 20. United States. doi:10.1063/1.4996687.
Yu, Chongqi, Harbich, Wolfgang, Sementa, Luca, Ghiringhelli, Luca, Aprá, Edoardo, Stener, Mauro, Fortunelli, Alessandro, and Brune, Harald. Mon . "Intense fluorescence of Au 20". United States. doi:10.1063/1.4996687.
@article{osti_1378040,
title = {Intense fluorescence of Au 20},
author = {Yu, Chongqi and Harbich, Wolfgang and Sementa, Luca and Ghiringhelli, Luca and Aprá, Edoardo and Stener, Mauro and Fortunelli, Alessandro and Brune, Harald},
abstractNote = {Ligand-protected Au clusters are non-bleaching fluorescence markers in bio- and medical applications. We show that their fluorescence is an intrinsic property of the Au cluster itself. We find a very intense and sharp fluorescence peak located at λ =739.2 nm (1.68 eV) for Au20 clusters in a Ne matrix held at 6 K. The fluorescence reflects the HOMO-LUMO diabatic bandgap of the cluster. The cluster shows a very rich absorption fine structure reminiscent of well defined molecule-like quantum levels. These levels are resolved since Au20 has only one stable isomer (tetrahedral), therefore our sample is mono-disperse in cluster size and conformation. Density-functional theory (DFT) and time-dependent DFT calculations clarify the nature of optical absorptionand predict both main absorption peaks and intrinsic fluorescence in good agreement with experiment.},
doi = {10.1063/1.4996687},
journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 7,
volume = 147,
place = {United States},
year = {2017},
month = {8}
}