A surface enhanced hyper-Raman scattering study of pyridine adsorbed onto silver: Experiment and theory

J. T. Golab, J. R. Sprague, K. T. Carron, George C Schatz, R. P. Van Duyne

Research output: Contribution to journalArticle

141 Citations (Scopus)

Abstract

This paper presents a combined experimental and theoretical study of the hyper-Raman spectrum of pyridine adsorbed onto roughened silver electrodes. The surface enhanced hyper-Raman spectra (SEHRS) were measured using a focused cw mode-locked Nd:YAG laser with a peak power density of approximately 10 7 W/cm2. Dominant bands in the pyridine spectra are the same (totally symmetric) bands as have been seen in the corresponding Raman (SERS) spectrum, although the relative intensities are different. To interpret these spectra, we present a semiempirical molecular orbital method for determining excitation energies, polarizability derivatives, and hyperpolarizability derivatives that is based on the π-electron Pariser-Parr-Pople (PPP) method. An empirical molecular force field is used to derive vibrational information, and the accuracy of the spectra is assessed by comparison with normal Raman spectra for liquid pyridine and with SERS spectra. The resulting SEHRS spectra are in good agreement with the measured spectra, particularly with respect to the intensity changes in the dominant lines in going from SERS to SEHRS. In addition, the theoretical/experimental comparisons indicate that SEHRS is more sensitive to adsorbate orientation than is SERS since the nontotally symmetric modes are predicted to be comparable in SEHRS (but not SERS) intensity to the totally symmetric modes for orientations other than perpendicular. Most important, a comparison of theoretical and experimental SEHRS/SERS ratios suggests that the enhancement factor associated with SEHRS is on the order of 1013 which is much larger than the 106 enhancement seen for SERS.

Original languageEnglish
Pages (from-to)7942-7951
Number of pages10
JournalJournal of Chemical Physics
Volume88
Issue number12
Publication statusPublished - 1988

Fingerprint

Silver
Raman scattering
pyridines
silver
Raman spectra
Experiments
pyridine
Derivatives
Excitation energy
augmentation
Molecular orbitals
Adsorbates
Laser modes
field theory (physics)
YAG lasers
radiant flux density
molecular orbitals
Electrodes
electrodes
Electrons

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

A surface enhanced hyper-Raman scattering study of pyridine adsorbed onto silver : Experiment and theory. / Golab, J. T.; Sprague, J. R.; Carron, K. T.; Schatz, George C; Van Duyne, R. P.

In: Journal of Chemical Physics, Vol. 88, No. 12, 1988, p. 7942-7951.

Research output: Contribution to journalArticle

Golab, J. T. ; Sprague, J. R. ; Carron, K. T. ; Schatz, George C ; Van Duyne, R. P. / A surface enhanced hyper-Raman scattering study of pyridine adsorbed onto silver : Experiment and theory. In: Journal of Chemical Physics. 1988 ; Vol. 88, No. 12. pp. 7942-7951.
@article{da059244c83443c7b6d4dd144c8bcc3f,
title = "A surface enhanced hyper-Raman scattering study of pyridine adsorbed onto silver: Experiment and theory",
abstract = "This paper presents a combined experimental and theoretical study of the hyper-Raman spectrum of pyridine adsorbed onto roughened silver electrodes. The surface enhanced hyper-Raman spectra (SEHRS) were measured using a focused cw mode-locked Nd:YAG laser with a peak power density of approximately 10 7 W/cm2. Dominant bands in the pyridine spectra are the same (totally symmetric) bands as have been seen in the corresponding Raman (SERS) spectrum, although the relative intensities are different. To interpret these spectra, we present a semiempirical molecular orbital method for determining excitation energies, polarizability derivatives, and hyperpolarizability derivatives that is based on the π-electron Pariser-Parr-Pople (PPP) method. An empirical molecular force field is used to derive vibrational information, and the accuracy of the spectra is assessed by comparison with normal Raman spectra for liquid pyridine and with SERS spectra. The resulting SEHRS spectra are in good agreement with the measured spectra, particularly with respect to the intensity changes in the dominant lines in going from SERS to SEHRS. In addition, the theoretical/experimental comparisons indicate that SEHRS is more sensitive to adsorbate orientation than is SERS since the nontotally symmetric modes are predicted to be comparable in SEHRS (but not SERS) intensity to the totally symmetric modes for orientations other than perpendicular. Most important, a comparison of theoretical and experimental SEHRS/SERS ratios suggests that the enhancement factor associated with SEHRS is on the order of 1013 which is much larger than the 106 enhancement seen for SERS.",
author = "Golab, {J. T.} and Sprague, {J. R.} and Carron, {K. T.} and Schatz, {George C} and {Van Duyne}, {R. P.}",
year = "1988",
language = "English",
volume = "88",
pages = "7942--7951",
journal = "Journal of Chemical Physics",
issn = "0021-9606",
publisher = "American Institute of Physics Publising LLC",
number = "12",

}

TY - JOUR

T1 - A surface enhanced hyper-Raman scattering study of pyridine adsorbed onto silver

T2 - Experiment and theory

AU - Golab, J. T.

AU - Sprague, J. R.

AU - Carron, K. T.

AU - Schatz, George C

AU - Van Duyne, R. P.

PY - 1988

Y1 - 1988

N2 - This paper presents a combined experimental and theoretical study of the hyper-Raman spectrum of pyridine adsorbed onto roughened silver electrodes. The surface enhanced hyper-Raman spectra (SEHRS) were measured using a focused cw mode-locked Nd:YAG laser with a peak power density of approximately 10 7 W/cm2. Dominant bands in the pyridine spectra are the same (totally symmetric) bands as have been seen in the corresponding Raman (SERS) spectrum, although the relative intensities are different. To interpret these spectra, we present a semiempirical molecular orbital method for determining excitation energies, polarizability derivatives, and hyperpolarizability derivatives that is based on the π-electron Pariser-Parr-Pople (PPP) method. An empirical molecular force field is used to derive vibrational information, and the accuracy of the spectra is assessed by comparison with normal Raman spectra for liquid pyridine and with SERS spectra. The resulting SEHRS spectra are in good agreement with the measured spectra, particularly with respect to the intensity changes in the dominant lines in going from SERS to SEHRS. In addition, the theoretical/experimental comparisons indicate that SEHRS is more sensitive to adsorbate orientation than is SERS since the nontotally symmetric modes are predicted to be comparable in SEHRS (but not SERS) intensity to the totally symmetric modes for orientations other than perpendicular. Most important, a comparison of theoretical and experimental SEHRS/SERS ratios suggests that the enhancement factor associated with SEHRS is on the order of 1013 which is much larger than the 106 enhancement seen for SERS.

AB - This paper presents a combined experimental and theoretical study of the hyper-Raman spectrum of pyridine adsorbed onto roughened silver electrodes. The surface enhanced hyper-Raman spectra (SEHRS) were measured using a focused cw mode-locked Nd:YAG laser with a peak power density of approximately 10 7 W/cm2. Dominant bands in the pyridine spectra are the same (totally symmetric) bands as have been seen in the corresponding Raman (SERS) spectrum, although the relative intensities are different. To interpret these spectra, we present a semiempirical molecular orbital method for determining excitation energies, polarizability derivatives, and hyperpolarizability derivatives that is based on the π-electron Pariser-Parr-Pople (PPP) method. An empirical molecular force field is used to derive vibrational information, and the accuracy of the spectra is assessed by comparison with normal Raman spectra for liquid pyridine and with SERS spectra. The resulting SEHRS spectra are in good agreement with the measured spectra, particularly with respect to the intensity changes in the dominant lines in going from SERS to SEHRS. In addition, the theoretical/experimental comparisons indicate that SEHRS is more sensitive to adsorbate orientation than is SERS since the nontotally symmetric modes are predicted to be comparable in SEHRS (but not SERS) intensity to the totally symmetric modes for orientations other than perpendicular. Most important, a comparison of theoretical and experimental SEHRS/SERS ratios suggests that the enhancement factor associated with SEHRS is on the order of 1013 which is much larger than the 106 enhancement seen for SERS.

UR - http://www.scopus.com/inward/record.url?scp=22844442386&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=22844442386&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:22844442386

VL - 88

SP - 7942

EP - 7951

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 12

ER -