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Title: Ligand-Enhanced Optical Response of Gold Nanomolecules and Its Fragment Projection Analysis: The Case of Au 30 (SR) 18

We investigate via first-principles simulations the optical absorption spectra of three different Au 30(SR) 18 monolayer-protected clusters (MPC): Au 30(StBu) 18, Au 30(SPh) 18, and Au 30(SPh-pNO 2) 18. Au 30(StBu) 18 is known in the literature, and its crystal structure is available. In contrast, Au 30(SPh) 18 and Au 30(SPh-pNO 2) 18 are two species that have been designed by replacing the tert-butyl organic residues of Au 30(StBu) 18 with aromatic ones so as to investigate the effects of ligand replacement on the optical response of Au nanomolecules. By analogy to a previously studied Au 23(SR)16– anionic species, despite distinct differences in charge and chemical composition, a substantial ligand enhancement of the absorption intensity in the optical region is also obtained for the Au 30(SPh-pNO 2) 18 MPC. Furthermore, the use of conjugated aromatic ligands with properly chosen electron-withdrawing substituents and exhibiting steric hindrance so as to also achieve charge decompression at the surface is therefore demonstrated as a general approach to enhancing the MPC photoabsorption intensity in the optical region. In addition, we here subject the ligand-enhancement phenomenon to a detailed analysis based on the fragment projection of electronic excited states and on induced transition densities, leading tomore » a better understanding of the physical origin of this phenomenon, thus opening avenues to its more precise control and exploitation.« less
Authors:
 [1] ;  [1] ;  [2] ;  [2] ; ORCiD logo [3] ; ORCiD logo [4] ; ORCiD logo [2] ; ORCiD logo [1]
  1. Consiglio Nazionale delle Ricerche (CNR), Pisa (Italy)
  2. Univ. of Trieste (Italy). Dept. of Chemical Science and Pharmacy
  3. Univ. of Mississippi, Oxford, MS (United States). Dept. of Chemistry and Biochemistry
  4. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab.
Publication Date:
Report Number(s):
PNNL-SA-123164
Journal ID: ISSN 1932-7447
Grant/Contract Number:
AC0576RL01830; CHE-1255519; 53999-ND5
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 8; Journal Issue: 2; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE
OSTI Identifier:
1343948

Sementa, Luca, Barcaro, Giovanni, Baseggio, Oscar, De Vetta, Martina, Dass, Amala, Aprà, Edoardo, Stener, Mauro, and Fortunelli, Alessandro. Ligand-Enhanced Optical Response of Gold Nanomolecules and Its Fragment Projection Analysis: The Case of Au 30 (SR) 18. United States: N. p., Web. doi:10.1021/acs.jpcc.6b12029.
Sementa, Luca, Barcaro, Giovanni, Baseggio, Oscar, De Vetta, Martina, Dass, Amala, Aprà, Edoardo, Stener, Mauro, & Fortunelli, Alessandro. Ligand-Enhanced Optical Response of Gold Nanomolecules and Its Fragment Projection Analysis: The Case of Au 30 (SR) 18. United States. doi:10.1021/acs.jpcc.6b12029.
Sementa, Luca, Barcaro, Giovanni, Baseggio, Oscar, De Vetta, Martina, Dass, Amala, Aprà, Edoardo, Stener, Mauro, and Fortunelli, Alessandro. 2017. "Ligand-Enhanced Optical Response of Gold Nanomolecules and Its Fragment Projection Analysis: The Case of Au 30 (SR) 18". United States. doi:10.1021/acs.jpcc.6b12029. https://www.osti.gov/servlets/purl/1343948.
@article{osti_1343948,
title = {Ligand-Enhanced Optical Response of Gold Nanomolecules and Its Fragment Projection Analysis: The Case of Au 30 (SR) 18},
author = {Sementa, Luca and Barcaro, Giovanni and Baseggio, Oscar and De Vetta, Martina and Dass, Amala and Aprà, Edoardo and Stener, Mauro and Fortunelli, Alessandro},
abstractNote = {We investigate via first-principles simulations the optical absorption spectra of three different Au30(SR)18 monolayer-protected clusters (MPC): Au30(StBu)18, Au30(SPh)18, and Au30(SPh-pNO2)18. Au30(StBu)18 is known in the literature, and its crystal structure is available. In contrast, Au30(SPh)18 and Au30(SPh-pNO2)18 are two species that have been designed by replacing the tert-butyl organic residues of Au30(StBu)18 with aromatic ones so as to investigate the effects of ligand replacement on the optical response of Au nanomolecules. By analogy to a previously studied Au23(SR)16– anionic species, despite distinct differences in charge and chemical composition, a substantial ligand enhancement of the absorption intensity in the optical region is also obtained for the Au30(SPh-pNO2)18 MPC. Furthermore, the use of conjugated aromatic ligands with properly chosen electron-withdrawing substituents and exhibiting steric hindrance so as to also achieve charge decompression at the surface is therefore demonstrated as a general approach to enhancing the MPC photoabsorption intensity in the optical region. In addition, we here subject the ligand-enhancement phenomenon to a detailed analysis based on the fragment projection of electronic excited states and on induced transition densities, leading to a better understanding of the physical origin of this phenomenon, thus opening avenues to its more precise control and exploitation.},
doi = {10.1021/acs.jpcc.6b12029},
journal = {Journal of Physical Chemistry. C},
number = 2,
volume = 8,
place = {United States},
year = {2017},
month = {1}
}