Sum-frequency generation from thiophenol on silver in the mid and far-IR

Braun, Roland; Casson, Brian D.; Bain, Colin D.; Ham, Eric; Vrehen, Q. H. F.; Eliel, E. R.; Briggs, Adam M.; Davies, Paul B.

doi:10.1063/1.478345

Cited by 66 publications

(68 citation statements)

References 13 publications

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“…By using broad-bandwidth sum frequency generation (BBSFG) [26][27][28] we recently analyzed the orientation of alkanethiols adsorbed on Au(111).…”

Section: Introductionmentioning

confidence: 99%

“…By using broad-bandwidth sum frequency generation (BBSFG) [26][27][28] we recently analyzed the orientation of alkanethiols adsorbed on Au(111). 29 It is worthwhile to examine the applicability of BBSFG in the TIR condition at metal interfaces to obtain SFG spectra with higher resolution.…”

Section: Introductionmentioning

confidence: 99%

“…The roughness is prerequisite for high sensitivity and can complicate the interpretation of the experimental data because of the orientational distribution of molecules in comparison with those adsorbed on a single crystal surface. It is therefore of crucial importance to assess the degree of the variation in orientation of molecules.By using broad-bandwidth sum frequency generation (BBSFG) [26][27][28] we recently analyzed the orientation of alkanethiols adsorbed on Au(111). …”

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confidence: 99%

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Total-internal-reflection Broad-bandwidth Sum Frequency Generation Spectroscopy of Hexadecanethiol Adsorbed on Thin Gold Film Deposited on CaF, 2

et al. 2003

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IntroductionFor the study of surface phenomena at various interfaces, the total internal reflection (TIR) condition has been used in a number of spectroscopic measurements, 1 such as fluorometry, 2-9 surface enhanced infrared spectroscopy (SEIRA), [10][11][12] second harmonic generation, [13][14][15][16][17][18][19][20][21] and sum frequency generation (SFG). [22][23][24][25] There are two advantages when one uses the TIR condition. First, both incident light to the interface and reflected light or generated light from the interface travel in only one of the two phases adjacent to the interface, which circumvents bulk absorption by the other phase. One corollary is the freedom of changing the composition of the adjacent phase that has a lower refractive index. Second, high sensitivity to the interfaces can be achieved owing to the enhancement of the electric field at the interfaces. 1 The TIR arrangement can be employed at metal interfaces if a very thin metal film is used to avoid the absorption of light. It has been successfully employed to detect adsorbed species on metal in the SEIRA, where the thickness of the metal film is about 10 nm on a transparent substrate. [10][11][12] Recently, Williams et al. showed that the TIR arrangement can also be employed to detect SFG signals from alkanethiols adsorbed on a thin gold film. 24 However, detailed analysis of the sum frequency vibrational spectra has not been reported. SFG in the TIR arrangement has some potential as a powerful tool to study molecular orientations at metal/liquid interfaces, such as electrochemical interfaces, because it is free from bulk absorption and has interfacial sensitivity in the order of nanometers. Unlike surface plasmon resonance and capacitance measurements that have been used as sensitive means of detecting adsorption and molecular interaction at the interfaces, TIR-SFG will enable us to obtain molecular information on the solution side of the interfaces. One drawback of the TIR arrangement is the roughness of the metal surfaces. The roughness is prerequisite for high sensitivity and can complicate the interpretation of the experimental data because of the orientational distribution of molecules in comparison with those adsorbed on a single crystal surface. It is therefore of crucial importance to assess the degree of the variation in orientation of molecules.By using broad-bandwidth sum frequency generation (BBSFG) [26][27][28] we recently analyzed the orientation of alkanethiols adsorbed on Au(111). 29It is worthwhile to examine the applicability of BBSFG in the TIR condition at metal interfaces to obtain SFG spectra with higher resolution. In the present paper, we report the results of TIR-BBSFG measurements for hexadecanethiol (HDT) adsorbed on a thin gold film on CaF2. We will show that BBSFG can be successfully employed in the orientation analysis of the HDT molecules and that the methyl groups of HDT are much more randomly orientated than those on Au(111) on mica. Experimental SubstrateA hemicylindrical CaF2 prism (Pier Optic...

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“…By using broad-bandwidth sum frequency generation (BBSFG) [26][27][28] we recently analyzed the orientation of alkanethiols adsorbed on Au(111).…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Total-internal-reflection Broad-bandwidth Sum Frequency Generation Spectroscopy of Hexadecanethiol Adsorbed on Thin Gold Film Deposited on CaF, 2

et al. 2003

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“…Table-top picosecond systems with a similar output power have been reported as well [18,19]. Higher output power (of ∼ 60 mW), combined with pulse durations in the range 500 fs-2 ps can be obtained in the wavelength range from 5 µm to 50 µm with a free electron laser source [20][21][22]. This is, however, not a table-top source but a facility.…”

Section: Introductionmentioning

confidence: 99%

“…The data were baseline-subtracted and normalized for acquisition time and incoming pulse energy. The spectra were fit according to the well-known formulas for the SFG intensity (see e.g., [22,29]):…”

Section: Vsfg Spectroscopy In the Fingerprint Regionmentioning

confidence: 99%

Generation and application of high power femtosecond pulses in the vibrational fingerprint region

Sugiharto¹,

Johnson²,

Aguiar³

et al. 2008

Appl. Phys. B

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We present a novel high power femtosecond infrared laser source, based on a three-stage chirped-pulse amplification scheme. Owing to the high power output of the Ti:sapphire amplifiers, it becomes routinely possible to produce femtosecond infrared laser pulses in the wavelength region of 2.6-20 µm with minimum pulse energies of 15 µJ, to our knowledge roughly an improvement of an order of magnitude. With such pulses we have performed femtosecond second-order nonlinear optical surface spectroscopy in the fingerprint region. We have probed the skeletal modes of the first few monolayers of a polymer/air interface in a femtosecond vibrational sum frequency generation experiment. This development opens up new possibilities to investigate surface structures and dynamics of, e.g., organo-metallic compounds, proteins, and peptides.PACS 82.35.Ps

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Sum Frequency Generation Study of CO Adsorption on Palladium Model Catalysts

Unterhalt

Galletto

Morkel

et al. 2001

phys. stat. sol. (a)

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In the present contribution CO adsorption on palladium aggregates was examined with IR-visible sum frequency generation vibrational spectroscopy. Supported Pd nanoparticles of different mean size and surface roughness were prepared by electron beam evaporation on an ordered Al 2 O 3 thin film formed on NiAl(110). SFG spectra were acquired for a wide range of CO pressures (from 1 Â 10 --7 to 200 mbar) at 190 to 300 K. At low pressure, evidence for a particle structure dependence of the CO adsorption geometry was found, with on-top CO sites significantly occupied on defective particles. On the other hand, under a high pressure regime, discrepancies between rough and smooth well-faceted particles were mostly reduced, with the relative fraction of on-top CO nearly equal for both cases. As a reference model, adsorption on well-defined Pd(111) single crystals was monitored as a function of CO pressure up to 1 bar and contrasted to the work done on aggregates. Under ultrahigh vacuum the SFG spectra on large Pd particles closely resembled the Pd(111) response. However, for pressures higher than 1 mbar at 190 K twofold bridge bonded sites were no longer populated on the Pd(111) surface while the bridge bonded occupancy was significant on Pd aggregates for all pressures studied.

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Sum-frequency generation from thiophenol on silver in the mid and far-IR

Cited by 66 publications

References 13 publications

Total-internal-reflection Broad-bandwidth Sum Frequency Generation Spectroscopy of Hexadecanethiol Adsorbed on Thin Gold Film Deposited on CaF, 2

Total-internal-reflection Broad-bandwidth Sum Frequency Generation Spectroscopy of Hexadecanethiol Adsorbed on Thin Gold Film Deposited on CaF, 2

Generation and application of high power femtosecond pulses in the vibrational fingerprint region

Sum Frequency Generation Study of CO Adsorption on Palladium Model Catalysts

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