Abstract
Normal and surface-enhanced Raman spectra for a set of substituted benzenethiols were measured experimentally and calculated from static polarizability derivatives determined with time-dependent density functional theory (TDDFT). Both silver and gold cluster-thiolate complexes were studied to investigate how the chemical enhancement varies with substituent. The experimental relative peak intensities and positions are well-matched by their theoretical counterparts. The static chemical enhancement of the ring stretching modes near 1600 cm-1 is determined experimentally and computationally for each derivative, and it is found that the experimental enhancement varies by a factor of 10 as a result of chemical substitution, with stronger electron donating groups on the benzene unit leading to higher enhancements. The calculated trends with substitution match experiment well, suggesting that TDDFT is describing the chemical effect qualitatively, if not quantitatively, in the static (low-frequency) limit. A two-state model is developed, providing qualitative insight into the results in terms of the variation of ligand-to-metal charge-transfer excitation energy with substitution.
| Original language | English |
|---|---|
| Pages (from-to) | 2599-2604 |
| Number of pages | 6 |
| Journal | Journal of Physical Chemistry Letters |
| Volume | 4 |
| Issue number | 16 |
| DOIs | |
| Publication status | Published - Aug 15 2013 |
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Keywords
- benzenethiol
- chemical mechanism of SERS
- INRA SERS substrate
- surface-enhanced Raman spectroscopy
ASJC Scopus subject areas
- Materials Science(all)
Cite this
A look at the origin and magnitude of the chemical contribution to the enhancement mechanism of surface-enhanced Raman spectroscopy (SERS) : Theory and experiment. / Valley, Nicholas; Greeneltch, Nathan; Van Duyne, Richard P.; Schatz, George C.
In: Journal of Physical Chemistry Letters, Vol. 4, No. 16, 15.08.2013, p. 2599-2604.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - A look at the origin and magnitude of the chemical contribution to the enhancement mechanism of surface-enhanced Raman spectroscopy (SERS)
T2 - Theory and experiment
AU - Valley, Nicholas
AU - Greeneltch, Nathan
AU - Van Duyne, Richard P.
AU - Schatz, George C
PY - 2013/8/15
Y1 - 2013/8/15
N2 - Normal and surface-enhanced Raman spectra for a set of substituted benzenethiols were measured experimentally and calculated from static polarizability derivatives determined with time-dependent density functional theory (TDDFT). Both silver and gold cluster-thiolate complexes were studied to investigate how the chemical enhancement varies with substituent. The experimental relative peak intensities and positions are well-matched by their theoretical counterparts. The static chemical enhancement of the ring stretching modes near 1600 cm-1 is determined experimentally and computationally for each derivative, and it is found that the experimental enhancement varies by a factor of 10 as a result of chemical substitution, with stronger electron donating groups on the benzene unit leading to higher enhancements. The calculated trends with substitution match experiment well, suggesting that TDDFT is describing the chemical effect qualitatively, if not quantitatively, in the static (low-frequency) limit. A two-state model is developed, providing qualitative insight into the results in terms of the variation of ligand-to-metal charge-transfer excitation energy with substitution.
AB - Normal and surface-enhanced Raman spectra for a set of substituted benzenethiols were measured experimentally and calculated from static polarizability derivatives determined with time-dependent density functional theory (TDDFT). Both silver and gold cluster-thiolate complexes were studied to investigate how the chemical enhancement varies with substituent. The experimental relative peak intensities and positions are well-matched by their theoretical counterparts. The static chemical enhancement of the ring stretching modes near 1600 cm-1 is determined experimentally and computationally for each derivative, and it is found that the experimental enhancement varies by a factor of 10 as a result of chemical substitution, with stronger electron donating groups on the benzene unit leading to higher enhancements. The calculated trends with substitution match experiment well, suggesting that TDDFT is describing the chemical effect qualitatively, if not quantitatively, in the static (low-frequency) limit. A two-state model is developed, providing qualitative insight into the results in terms of the variation of ligand-to-metal charge-transfer excitation energy with substitution.
KW - benzenethiol
KW - chemical mechanism of SERS
KW - INRA SERS substrate
KW - surface-enhanced Raman spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=84882313405&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84882313405&partnerID=8YFLogxK
U2 - 10.1021/jz4012383
DO - 10.1021/jz4012383
M3 - Article
AN - SCOPUS:84882313405
VL - 4
SP - 2599
EP - 2604
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
SN - 1948-7185
IS - 16
ER -