Relative and Absolute Raman Scattering Cross Sections in Liquids

Colles, M. J.; Griffiths, James E.

doi:10.1063/1.1677709

Cited by 118 publications

(102 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is interesting that the Raman depolarization ratio for the 2882 cm -1 and 2938 cm -1 peaks in the gaseous CH 3 CH 2 OH measured in this work are quite close to those of the corresponding peaks in the liquid ethanol as measured by Colles et al 17 This clearly indicates that the symmetry properties of these two peaks changed insignificantly going from the gaseous phase to the liquid phase. In contrast, the F value for the 2983 cm -1 peaks in the gaseous CH 3 CH 2 OH is 0.151, quite significantly different from the liquid ethanol value of 0.31.…”

Section: Raman Spectra Of Gaseous Ethanol In the C-hsupporting

confidence: 86%

“…In contrast, the F value for the 2983 cm -1 peaks in the gaseous CH 3 CH 2 OH is 0.151, quite significantly different from the liquid ethanol value of 0.31. 17 This indicates a significant increase of the asymmetric character of this peak in the liquid phase compared to the gaseous phase, consistent with the much stronger CH 3 -as peak in the liquid CH 3 CD 2 OH spectra ( Figure 5) compared to that in the gaseous CH 3 CD 2 OH spectra ( Figure 3). Because the solvent effects on molecules at the liquid interface are generally in between those in the gaseous and liquid phases, [36][37][38] the small changes between the gaseous and liquid Raman spectra also explains why the spectral features in the SFG-VS spectra of the ethanol molecule at the air/liquid interface are essentially the same as those in the gaseous and liquid phases.…”

Section: Raman Spectra Of Gaseous Ethanol In the C-hsupporting

confidence: 67%

See 1 more Smart Citation

New C−H Stretching Vibrational Spectral Features in the Raman Spectra of Gaseous and Liquid Ethanol

et al. 2007

View full text Add to dashboard Cite

Traditionally, the Raman spectrum of ethanol in the C-H vibrational stretching region between 2800 cm -1 and 3100 cm -1 had been assigned as three bands of the -CH 2 symmetric stretching, the -CH 3 symmetric stretching, and the -CH 3 antisymmetric stretching. In this report, new Raman spectral features were observed for ethanol and two deuterated ethanols, that is, CD 3 CH 2 OH and CH 3 CD 2 OH, in both gaseous and liquid phases with polarized photoacoustic Raman spectroscopy (PARS) as well as normal Raman spectroscopy. With the aid of depolarization ratio measurements and quantum chemical calculations, different assignments were presented to the complex spectral features in the ethanol Raman spectra. In the gaseous ethanol spectra, the band at ∼2882 cm -1 was assigned to the overlapping symmetric stretching vibrational modes of both -CH 2 and -CH 3 ; the band at ∼2938 cm -1 was assigned to the two symmetric -CH 3 Fermi resonance modes and the weak -CH 2 antisymmetric stretching mode; and the band at ∼2983 cm -1 was assigned to the symmetric -CH 2 Fermi resonance mode and the weak -CH 3 antisymmetric stretching mode. The liquid ethanol spectral features are similar to the gaseous spectra with a much stronger -CH 3 antisymmetric stretching mode and a red shift of about 10 cm -1 , which can be attributed to the effects of solvent interactions. The new assignments of both the gaseous and liquid ethanol spectra not only confirmed the recent results from the sum-frequency generation vibrational spectroscopy studies of the ethanol molecules at the air/liquid interface but the differences in the gaseous and liquid phases, as well as at the interfaces, can also provide detailed experimental evidence in understanding of the molecular interactions and dynamics of the ethanol molecule in different chemical environments.

show abstract

Section: Raman Spectra Of Gaseous Ethanol In the C-hsupporting

confidence: 86%

Section: Raman Spectra Of Gaseous Ethanol In the C-hsupporting

confidence: 67%

New C−H Stretching Vibrational Spectral Features in the Raman Spectra of Gaseous and Liquid Ethanol

et al. 2007

View full text Add to dashboard Cite

show abstract

“…This is done by dividing the ADC counts with the corresponding integration time (typically 1-5 seconds) and the measured sensitivity (19x10 6 counts/ms/μW) of the spectrometer near the wavelength corresponding to the IPA peak. We take σ = 7.9x10 -31 cm 2 /sr/molecule for the 819 cm -1 line which is calculated by using the value measured at 488 nm in [18] and applying the 1/λ 0 4 dependence of the scattering cross-section [4]. Four chips containing different waveguide dimensions and geometries were diced from different locations on a wafer and measured three times for the experiments.…”

Section: Measurement Of η 0 For Strip and Slot Si 3 N 4 Waveguidesmentioning

confidence: 99%

“…where, Δ(σ)( = ± 10% ) is the error in the cross-section value [18], Δ(P tx ) (= ± 20%) is the error in the measurement of transmitted power, Δ(P col ) (= ± 25%) is the error in the measurement of the sensitivity of the spectrometer. The last term in Eq.…”

Section: Measurement Of η 0 For Strip and Slot Si 3 N 4 Waveguidesmentioning

confidence: 99%

Efficiency of evanescent excitation and collection of spontaneous Raman scattering near high index contrast channel waveguides

Dhakal¹,

Raza²,

Peyskens³

et al. 2015

Opt. Express

View full text Add to dashboard Cite

Abstract:We develop and experimentally verify a theoretical model for the total efficiency η 0 of evanescent excitation and subsequent collection of spontaneous Raman signals by the fundamental quasi-TE and quasi-TM modes of a generic photonic channel waveguide. Single-mode silicon nitride (Si 3 N 4 ) slot and strip waveguides of different dimensions are used in the experimental study. Our theoretical model is validated by the correspondence between the experimental and theoretical absolute values within the experimental errors. We extend our theoretical model to siliconon-insulator (SOI) and titanium dioxide (TiO 2 ) channel waveguides and study η 0 as a function of index contrast, polarization of the mode and the geometry of the waveguides. We report nearly 2.5 (4 and 5) times larger η 0 for the fundamental quasi-TM mode when compared to η 0 for the fundamental quasi-TE mode of a typical Si 3 N 4 (TiO 2 and SOI) strip waveguide. η 0 for the fundamental quasi-TE mode of a typical Si 3 N 4, (TiO 2 and SOI) slot waveguide is about 7 (22 and 90) times larger when compared to η 0 for the fundamental quasi-TE mode of a strip waveguide of the similar dimensions. We attribute the observed enhancement to the higher electric field discontinuity present in high index contrast waveguides.

show abstract

“…This number is in good agreement veith the value A~" s = 5.7 cm -I calculated from eq. (8) using the material parameters of CC13 CH 3 and the experimental data :n 2 = 1.6 × 10-13esu;~" L = 18990 cm -1, G = 75; tp = 7 ps, and g = 8 X 10 -1° cm/W [11]. As predicted from eq.…”

Section: (3)mentioning

confidence: 99%

Frequency shifts in stimulated Raman scattering

Kaiser

1980

Optics Communications

View full text Add to dashboard Cite

The nonresonant contributions to the nonlinear susceptibility x (3) produce a frequency chirp during stimulated Raman scattering. In the case of transient stimulated Raman scattering, the spectrum of the generated Stokes pulse is found at higher frequencies than expected from spontaneous Raman data. The frequency difference can be calculated from the theory of stimulated Raman scattering.It has been shown in numerous papers that an intense electromagnetic wave of frequency COL, travelling through a Raman active medium, is able to generate a strong Stokes shifted collinear wave at frequency coS. In most experimental investigations the Stokes shift coo = col --coS of the stimulated Raman process was found to be equal to the Stokes shift known from spontaneous Raman measurements [ 1 ]. In contradiction, there exists a number of papers where deviations in the Stokes shifts between stimulated and spontaneous Raman scattering were reported [2].In this note we present a theoretical and experimental study of the stimulated Raman process taking into account the self-phase modulation of the laser and Stokes wave. It will be shown that under quasistationary conditions the stimulated Stokes emission has the same Stokes shift as spontaneous Raman scattering. For the transient stimulated Raman process the situation is different. Theory predicts and experiments confirm a smaller Stokes shift, i.e. a higher Stokes frequency. For clarity, we consider here a specific case, Raman scattering of a molecular vibration in liquids. The theoretical discussion is quite general being applicable to other Raman type process as well.The nonlinear response of the molecules is represented by the nonlinear polarisation pNL, which may be separated into two parts: A resonant contribution PR NL due to the molecular transition of interest with a Raman susceptibility ~a/~q and a nonresonant part NL PNR due to the electronic states of the molecules [3].N is the number density of the molecules and denotes the expectation value of the normal mode operator q for the transition. For simplicity we make two assumptions: (i) A highly polarized Raman line is investigated, i.e. Oa/aq is a scalar. coO and m represent the transition frequency and the reduced mass, respectively, T 2 the dephasing time and n' is the occupation probability of the first excited vibrational level. For the system considered here we have a small population, i.e. n' < 1.For the light fields and the coherent material excitation, we make the ansatz of plane waves propagating in the x-direction: E = ~ {~ Ejexp(-ico/t + ikix + i~b/) + cc 1and ~q) = -~i{Q exp(-icoqt + ikqx + i~bq) + cc}.

show abstract

Relative and Absolute Raman Scattering Cross Sections in Liquids

Cited by 118 publications

References 14 publications

New C−H Stretching Vibrational Spectral Features in the Raman Spectra of Gaseous and Liquid Ethanol

New C−H Stretching Vibrational Spectral Features in the Raman Spectra of Gaseous and Liquid Ethanol

Efficiency of evanescent excitation and collection of spontaneous Raman scattering near high index contrast channel waveguides

Frequency shifts in stimulated Raman scattering

Contact Info

Product

Resources

About