The Reactions of C2H2 and CH3C2H on Ag Powder

AbstractAg powder is activated by pulsing it with NO2 gas which forms fresh Ag microclusters. This powder is then exposed to subsequent pulses of C2H2 or CH3C2H (3.7% in N2 ). The surface enhanced Raman scattering (SERS) spectra show dramatic intensity variations due to rapid changes in adatom concentration. Normalization of these time-dependent SERS spectra to the background scattering intensity, which is proportional to the adatom concentration, provides spectra which represent adsorbate coverage if major surface reconstruction does not occur. The temporal development of the SERS spectra of C2H2 shows rapid degradation with no evidence for adsorbed species. In contrast, propyne reacts more slowly, as evidenced by the behavior of the intensity at 1980cm−1 due to adsorbed -C2-. The reactions observed are in accord with the models developed by Barteau and Madix[1] and Vohs, Carney, and Barteau[2]. Exposure to both alkynes results in the appearance of SERS active NO, an adsorbant not previously observed at room temperature. Ellipsometric measurements are consistent with the presence of a carbon overlayer, which may stabilize the NO and render the system inert to further chemical reaction.

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Off-Line Direct Deposition Gas Chromatography/Surface-Enhanced Raman Scattering and the Ramifications for On-Line Measurements

Applied Spectroscopy ◽

10.1366/000370205774783160 ◽

2005 ◽

Vol 59 (11) ◽

pp. 1305-1309 ◽

Cited By ~ 12

Author(s):

David A. Heaps ◽

Peter R. Griffiths

Keyword(s):

Gas Chromatography ◽

Vapor Deposition ◽

Physical Vapor Deposition ◽

Room Temperature ◽

Warm Up ◽

Surface Enhanced ◽

Surface Enhanced Raman ◽

On Line ◽

Enhanced Raman Scattering ◽

Moving Liquid

Surface-enhanced Raman spectra (SERS) of molecules separated by gas chromatography (GC) were measured off-line by condensing the analyte on a moving, liquid-nitrogen-cooled ZnSe window on which a 5 nm layer of silver had been formed by physical vapor deposition. After the components that eluted from the chromatograph had been deposited, the substrate was allowed to warm up to room temperature and transferred to the focus of a Raman microspectrometer where the spectrum of each component was measured. Band intensities in the spectrum of 3 ng of caffeine prepared in this way were approximately the same as in the spectrum of bulk caffeine. By making some logical assumptions, it was shown that identifiable GC/SERS spectra of 30 pg of many molecules could be measured over a 300 cm−1 region in real-time and that if an optimized substrate were used the minimum identifiable quantity could be reduced to 1 pg or less.

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Roles of Interfacial Functions in Analytical Chemistry. Quantitative examinations of the near-infrared FT-surface enhanced Raman scattering intensity of sample adsorbed on Au colloid.

BUNSEKI KAGAKU ◽

10.2116/bunsekikagaku.47.1005 ◽

1998 ◽

Vol 47 (12) ◽

pp. 1005-1011 ◽

Cited By ~ 1

Author(s):

Tetsuo OHNISHI ◽

Seiichiro HIGUCHI ◽

Yohichi GOHSHI

Keyword(s):

Analytical Chemistry ◽

Raman Scattering ◽

Near Infrared ◽

Surface Enhanced Raman Scattering ◽

Scattering Intensity ◽

Surface Enhanced ◽

Surface Enhanced Raman ◽

Enhanced Raman Scattering

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SERS Observation of the Adsorption Behavior of O2, H2O, and SO2 on Silver Powder Surfaces at Nearly Real Environmental Conditions

Applied Spectroscopy ◽

10.1366/0003702894203354 ◽

1989 ◽

Vol 43 (2) ◽

pp. 239-245 ◽

Cited By ~ 10

Author(s):

Hideyuki Matsuta ◽

Kichinosuke Hirokawa

Keyword(s):

Environmental Conditions ◽

Atomic Oxygen ◽

Room Temperature ◽

Silver Powder ◽

Surface Species ◽

Superoxide Ion ◽

Surface Enhanced ◽

High Partial Pressure ◽

Surface Enhanced Raman ◽

Enhanced Raman Scattering

The interaction of O2, H2O, and SO2 on silver powder prepared from the reduction of AgNO3 by NaBH4 was studied by surface-enhanced Raman scattering (SERS) at room temperature. The presence of H2O of about 103 Pa and O2 of about 104-105 Pa was necessary for observation of SERS peaks of SO32− and SO42−. The superoxide ion O2- was observed under high partial pressure for O2 conditions. SERS peaks of atomic oxygen, superoxide ion O2-, SO32−, and SO42− disappeared on evacuation. SERS peaks of surface species such as Ag2O did not disappear on evacuation.

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Surface-enhanced Raman scattering of pyrazine on Au5Al5 bimetallic nanoclusters

RSC Advances ◽

10.1039/c6ra28240g ◽

2017 ◽

Vol 7 (20) ◽

pp. 12170-12178 ◽

Cited By ~ 3

Author(s):

Quanjiang Li ◽

Qianqian Ding ◽

Weihua Lin ◽

Jiangcai Wang ◽

Maodu Chen ◽

...

Keyword(s):

Density Functional ◽

Dft Method ◽

Time Dependent ◽

Functional Theory ◽

Bimetallic Nanoclusters ◽

Surface Enhanced ◽

Td Dft ◽

Surface Enhanced Raman ◽

Enhanced Raman Scattering ◽

Dependent Density

In this study, we theoretically investigated the Raman and absorption spectra of pyrazine adsorbed on Au5Al5 bimetallic nanoclusters by a time-dependent density functional theory (TD-DFT) method.

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