Vibrational spectroscopy of interfaces by infrared–visible sum frequency generation

Buck, Manfred; Himmelhaus, Michael

doi:10.1116/1.1414120

Cited by 249 publications

(301 citation statements)

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“…In this context, nonlinear vibrational sum frequency generation (VSFG) spectroscopy offers the needed inherent surface specificity on the nanolayer scale. The method, which has already found numerous applications in various areas such as surface dynamics and catalysis [Buck and Himmelhaus, 2001;Lambert et al, 2005], spectroscopy of air-aqueous interfaces , and for the examination of environmental and biomolecular surfaces [Geiger, 2009;Yatawara et al, 2009], was recently shown by us to be suitable for investigating natural sea surface nanolayers as well [Laß et al, 2010].…”

Section: Introductionmentioning

confidence: 99%

Revealing structural properties of the marine nanolayer from vibrational sum frequency generation spectra

Laß¹,

Friedrichs²

2011

J. Geophys. Res.

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Natural nanolayers originating from sea surface and subsurface water samples collected in the Baltic Sea have been investigated using surface‐sensitive vibrational sum frequency generation (VSFG) spectroscopy. Distinct spectral signatures of CH and OH bond stretch vibrations have been detected at wavenumbers ranging from 2700 to 3900 cm−1. Measured water‐air interface spectra as well as observed signal intensity trends are discussed in terms of composition and structure of the natural organic nanolayer. Reasoning was based on the comparison with reference spectra, spectral trends inferred from previous VSFG studies, reported average composition of dissolved organic matter in seawater, and simplified assumption that surfactants can be classified as soluble (wet) and insoluble (dry) surfactants. Wet surfactants have been found to be dominant, and often lipid‐like compounds form a very dense surfactant nanolayer. Supported by comparison spectra of xanthan gum solutions, the observed VSFG spectral signatures were tentatively assigned to lipopolysaccharides or other lipid‐like compounds embedded in colloidal matrices of polymeric material. In addition, VSFG spectra of a polluted harbor water sample and a water sample covered with diesel oil are reported.

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Section: Introductionmentioning

confidence: 99%

Revealing structural properties of the marine nanolayer from vibrational sum frequency generation spectra

Laß¹,

Friedrichs²

2011

J. Geophys. Res.

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“…It can be shown that in many cases the generated SFG signal intensity simply depends on the square of the secondorder susceptibility (Buck and Himmelhaus 2001). χ (2) can be interpreted as a macroscopic average of the probed molecular hyperpolarizabilities β such that the overall SFG intensity is proportional to the number density of SFG active surface oscillators N squared:…”

Section: Introductionmentioning

confidence: 99%

“…In principle, these limitations can be overcome by sensitive detection methods that are limited to a well-defined layer by their inherent physical properties. A very promising method that already has led to important findings in various fields of basic research, such as surface catalysis and liquid-gas interface sciences, is the so-called infrared-visible or vibrational sum-frequency generation spectroscopy (IV-SFG, VSFG) (Buck and Himmelhaus 2001;Lambert et al 2005). The method has found first applications in environmental sciences as well (Geiger 2009).…”

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confidence: 99%

Vibrational sum‐frequency generation as a probe for composition, chemical reactivity, and film formation dynamics of the sea surface nanolayer

Laβ

Kleber

Friedrichs

2010

Limnology & Ocean Methods

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Vibrational Sum Frequency Generation (VSFG) is a surface sensitive nonlinear laser spectroscopic technique, which has been widely used in physics and physical chemistry to investigate interface processes and heterogeneous chemistry. As the technique advances from basic to applied research, we have assessed its suitability for investigations of natural air-water interfaces, which are typically covered with an organic nanolayer. Vibrational spectra of natural sea surface nanolayer samples are presented. Strong signals attributable to the alkyl chains of lipids and indications for more or less soluble carbohydrate material have been found. Furthermore, the use of VSFG spectroscopy as a time-resolved detection tool for monitoring surface layer formation and its reactive decay is demonstrated. Ozone-induced film oxidation served as an example. We successfully applied VSFG to characterize the efficiency of a surface water screen sampler as well. Overall, VSFG spectroscopy turns out to be a versatile tool that can provide valuable information about composition, structure, chemical reactivity, and film formation dynamics of the sea surface nanolayer.*Corresponding author: E-mail: friedrichs@phc.uni-kiel.de AcknowledgmentsWe are indebted to the people from the Boknis Eck project at IFM-GEOMAR for the opportunity to take samples during their sample cruises, and to captain and crew of the R/V Littorina for their support during the cruises. Thanks to Friedrich Temps and Doug Wallace for helpful discussions. Financial support by the German Science Foundation (DFG -EC 80) in the framework of the cluster of excellence The Future Ocean is gratefully acknowledged.

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“…1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25 To simply put it, SHG is the second order nonlinear process where two photons with the same fundamental frequency (ω) interact with a nonlinear medium simultaneously to generate a photon with the second harmonic frequency (2ω). If the two fundamental frequencies are not the same, a photon at the sum of these two frequencies can be generated from the so-called SFG process.…”

Section: Introductionmentioning

confidence: 99%

Microscopic molecular optics theory of surface second harmonic generation and sum-frequency generation spectroscopy based on the discrete dipole lattice model

Dong¹,

Yuan²,

Liu³

et al. 2008

International Reviews in Physical Chemistry

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Two crucial issues in the interface studies with the interface specific nonlinear spectroscopy are on how to describe the macroscopic dielectric constant of the molecularly thin layer and how to calculate the anisotropic two dimensional microscopic local field effect. In the currently accepted models of the nonlinear optics, the nonlinear radiation was treated as the result of an infinitesimally thin polarization sheet layer, and a three layer model was generally employed. The direct consequence of this approach is that an apriori dielectric constant, which still does not have a clear definition, has to be assigned to this polarization layer. Because the Second Harmonic Generation (SHG) and the Sum-Frequency Generation vibrational Spectroscopy (SFG-VS) have been proven as the sensitive probes for interfaces with the submonolayer coverage, the treatment based on the more realistic discrete induced dipole model needs to be developed. Here we show that following the molecular optics theory approach the SHG, as well as the SFG-VS, radiation from the monolayer or submonolayer at an interface can be rigorously treated as the radiation from an induced dipole lattice at the interface. In this approach, the introduction of the polarization sheet is no longer necessary. Therefore, the ambiguity of the unaccounted dielectric constant of the polarization layer is no longer an issue. Moreover, the anisotropic two dimensional microscopic local field factors can be explicitly expressed with the linear polarizability tensors of the interfacial molecules. Based on the planewise dipole sum rule in the molecular monolayer, crucial experimental tests of this microscopic treatment with SHG and SFG-VS are discussed. Many puzzles in the literature of surface SHG and SFG spectroscopy studies can also be understood or resolved in this framework. This new treatment may provide a solid basis for the quantitative analysis in the surface SHG and SFG studies.

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Vibrational spectroscopy of interfaces by infrared–visible sum frequency generation

Cited by 249 publications

References 257 publications

Revealing structural properties of the marine nanolayer from vibrational sum frequency generation spectra

Revealing structural properties of the marine nanolayer from vibrational sum frequency generation spectra

Vibrational sum‐frequency generation as a probe for composition, chemical reactivity, and film formation dynamics of the sea surface nanolayer

Microscopic molecular optics theory of surface second harmonic generation and sum-frequency generation spectroscopy based on the discrete dipole lattice model

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