<scp>R</scp>aman Spectroscopy of Gases

Weber, Alfons

doi:10.1002/0470027320.s0105m

Cited by 3 publications

(3 citation statements)

References 164 publications

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“…Raman spectroscopy monitors the vibrations of gas, liquid and solid samples 23–25. H 2 O is a relatively weak Raman scatterer.…”

Section: Techniques For Studying Protein Foldingmentioning

confidence: 99%

“…22 Raman spectroscopy monitors the vibrations of gas, liquid, and solid samples. [23][24][25] H 2 O is a relatively weak Raman scatterer. This enables Raman studies of biological molecules in H 2 O. Raman spectroscopy is an inelastic light-scattering phenomenon where the incident electromagnetic field interacts with a molecule such that there is an exchange of a quantum of vibrational energy between the two, resulting in a vibrational frequency difference between the incident and scattered light.…”

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confidence: 99%

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Elucidating Peptide and Protein Structure and Dynamics: UV Resonance Raman Spectroscopy

Oladepo

Xiong

Hong

et al. 2011

J. Phys. Chem. Lett.

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UV resonance Raman spectroscopy (UVRR) is a powerful method that has the requisite selectivity and sensitivity to incisively monitor biomolecular structure and dynamics in solution. In this perspective, we highlight applications of UVRR for studying peptide and protein structure and the dynamics of protein and peptide folding. UVRR spectral monitors of protein secondary structure, such as the Amide III 3 band and the C α -H band frequencies and intensities can be used to determine Ramachandran Ψ angle distributions for peptide bonds. These incisive, quantitative glimpses into conformation can be combined with kinetic T-jump methodologies to monitor the dynamics of biomolecular conformational transitions. The resulting UVRR structural insight is impressive in that it allows differentiation of, for example, different α-helix-like states that enable differentiating π-and 3 10 -states from pure α-helices. These approaches can be used to determine the Gibbs free energy landscape of individual peptide bonds along the most important protein (un)folding coordinate. Future work will find spectral monitors that probe peptide bond activation barriers that control protein (un)folding mechanisms. In addition, UVRR studies of sidechain vibrations will probe the role of side chains in determining protein secondary, tertiary and quaternary structures. KeywordsProtein folding; melting dynamics; T-jump; UV resonance Raman spectroscopy; UVRR transient spectra; protein (un)folding kinetics The protein folding problemAn understanding of the mechanism(s) of protein folding, whereby the ribosome synthesized biopolymer folds into its native protein is arguably one of the most important unsolved problem in biology. [1][2][3][4][5][6][7] The primary sequence of many or most proteins encodes both the native structure as well as the folding mechanism pathway to the native structure. [8][9][10] An understanding of the encoded protein folding "rules" would dramatically speed insight into protein structure and function.A number of mechanisms have been proposed that differ in the order of folding events. The framework model 11 and the diffusion-collision model 12 propose that the initial step in folding involves formation of native-like secondary structural units, while the hydrophobic collapse model and the nucleation-condensation model 13 suggest that hydrophobic or nucleating domains fold first, and that these structures drive the subsequent formation of secondary structure. Recent energy landscape models 14 propose the occurrence of funnelshaped folding energy landscapes, where the native state is accessed via a strategically * To whom correspondence should be addressed asher@pitt.edu NIH Public Access Thus, tuning the UVRR excitation wavelengths, allows the probing of different chromophoric segments of a macromolecule. Another advantage of deep UV Raman measurements is that there is no interference from molecular relaxed fluorescence. 42 In addition, UVRR can also be used in pump-probe measurements to give kinetic information on ...

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“…Raman spectroscopy monitors the vibrations of gas, liquid and solid samples 23–25. H 2 O is a relatively weak Raman scatterer.…”

Section: Techniques For Studying Protein Foldingmentioning

confidence: 99%

mentioning

confidence: 99%

Elucidating Peptide and Protein Structure and Dynamics: UV Resonance Raman Spectroscopy

Oladepo

Xiong

Hong

et al. 2011

J. Phys. Chem. Lett.

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“…Note that for all of these implementations, the measurements have been limited to nighttime due to the fact that the Raman signal from liquid water is generally weaker than that from water vapor and covers a spectrum more than an order of magnitude wider ('5 versus 0.3 nm). The liquid water signals are generally weaker despite a cross section approximately 5 times higher (Weber 1979;Slusher and Derr 1975) than water vapor because of the typically lower number density of liquid versus vapor in a cloud. The channel characteristics are shown in Table 1.…”

Section: ) Liquid Water Measurementsmentioning

confidence: 99%

Airborne and Ground-Based Measurements Using a High-Performance Raman Lidar

Whiteman

Rush

Rabenhorst

et al. 2010

Journal of Atmospheric and Oceanic Technology

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A high-performance Raman lidar operating in the UV portion of the spectrum has been used to acquire, for the first time using a single lidar, simultaneous airborne profiles of the water vapor mixing ratio, aerosol backscatter, aerosol extinction, aerosol depolarization and research mode measurements of cloud liquid water, cloud droplet radius, and number density. The Raman Airborne Spectroscopic Lidar (RASL) system was installed in a Beechcraft King Air B200 aircraft and was flown over the mid-Atlantic United States during JulyAugust 2007 at altitudes ranging between 5 and 8 km. During these flights, despite suboptimal laser performance and subaperture use of the telescope, all RASL measurement expectations were met, except that of aerosol extinction. Following the Water Vapor Validation Experiment-Satellite/Sondes (WAVES_2007) field campaign in the summer of 2007, RASL was installed in a mobile trailer for groundbased use during the Measurements of Humidity and Validation Experiment (MOHAVE-II) field campaign held during October 2007 at the Jet Propulsion Laboratory's Table Mountain Facility in southern California. This ground-based configuration of the lidar hardware is called Atmospheric Lidar for Validation, Interagency Collaboration and Education (ALVICE). During the MOHAVE-II field campaign, during which only nighttime measurements were made, ALVICE demonstrated significant sensitivity to lower-stratospheric water vapor. Numerical simulation and comparisons with a cryogenic frost-point hygrometer are used to demonstrate that a system with the performance characteristics of RASL-ALVICE should indeed be able to quantify water vapor well into the lower stratosphere with extended averaging from an elevated location like Table Mountain. The same design considerations that optimize Raman lidar for airborne use on a small research aircraft are, therefore, shown to yield significant dividends in the quantification of lower-stratospheric water vapor. The MOHAVE-II measurements, along with numerical simulation, were used to determine that the likely reason for the suboptimal airborne aerosol extinction performance during the WAVES_2007 campaign was a misaligned interference filter. With full laser power and a properly tuned interference filter, RASL is shown to be capable of measuring the main water vapor and aerosol parameters with temporal resolutions of between 2 and 45 s and spatial resolutions ranging from 30 to 330 m from a flight altitude of 8 km with precision of generally less than 10%, providing performance that is competitive with some airborne Differential Absorption Lidar (DIAL) water vapor and High Spectral Resolution Lidar (HSRL) aerosol instruments. The use of diode-pumped laser technology would improve the performance of an airborne Raman lidar and permit additional instrumentation to be carried on board a small research aircraft. The combined airborne and ground-based measurements presented here demonstrate a level of versatility in Raman lidar that may be impossible to duplicate with any o...

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The collective vibration modes of hydrogen bonds as a gauge of water states in fruits and leaves

et al. 2006

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The new con cep tion of the col lec tive vi bra tion modes (CVM) of the wa ter me dium is used to study wa ter states in tis sues (leaves and fruit). The CVM of the hy dro gen bond (HB) nets were stud ied by the meth ods of the Raman and in fra red (IR) spec tros copy in the re gion of the low fre quency LO and TO modes and high fre quency sum mary tones of these modes with fun da men tal vi bra tions. The fre quency and in ten sity changes in the col lec tive modes in com par i son with dis tilled wa ter are in dic a tive of the HB nets or dered or dis or dered. It was found that in plant tis sue the wa ter can be both in dis or dered state as com pared to dis tilled wa ter and in more col lec tiv ized state. The ex is tence of four dif fer ent wa ter states in leaves has been es tab lished.

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Raman Spectroscopy of Gases

Abstract: The sections in this article are Introduction Spontaneous R aman Spectroscopy High‐Resolution Rotation–Vibration Spectra Use of Interferometers R aman Line Widths Intensity Alternation … Show more

Cited by 3 publications

References 164 publications

Elucidating Peptide and Protein Structure and Dynamics: UV Resonance Raman Spectroscopy

Elucidating Peptide and Protein Structure and Dynamics: UV Resonance Raman Spectroscopy

Airborne and Ground-Based Measurements Using a High-Performance Raman Lidar

The collective vibration modes of hydrogen bonds as a gauge of water states in fruits and leaves

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