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Showing papers on "Raman spectroscopy published in 1985"


Journal ArticleDOI
TL;DR: The surface-enhanced Raman scattering (SERS) effect was first discovered by Fleischmann, Van Duyne, Creighton, and Creighton as discussed by the authors, who showed that molecules adsorbed on specially prepared silver surfaces produce a Raman spectrum that is at times a millionfold more intense than expected.
Abstract: In 1978 it was discovered, largely through the work of Fleischmann, Van Duyne, Creighton, and their coworkers that molecules adsorbed on specially prepared silver surfaces produce a Raman spectrum that is at times a millionfold more intense than expected. This effect was dubbed surface-enhanced Raman scattering (SERS). Since then the effect has been demonstrated with many molecules and with a number of metals, including Cu, Ag, Au, Li, Na, K, In, Pt, and Rh. In addition, related phenomena such as surface-enhanced second-harmonic generation, four-wave mixing, absorption, and fluorescence have been observed. Although not all fine points of the enhancement mechanism have been clarified, the majority view is that the largest contributor to the intensity amplification results from the electric field enhancement that occurs in the vicinity of small, interacting metal particles that are illuminated with light resonant or near resonant with the localized surface-plasmon frequency of the metal structure. Small in this context is gauged in relation to the wavelength of light. The special preparations required to produce the effect, which include among other techniques electrochemical oxidation-reduction cycling, deposition of metal on very cold substrates, and the generation of metal-island films and colloids, is now understood to be necessary as a means of producing surfaces with appropriate electromagnetic resonances that may couple to electromagnetic fields either by generating rough films (as in the case of the former two examples) or by placing small metal particles in close proximity to one another (as in the case of the latter two). For molecules chemisorbed on SERS-active surface there exists a "chemical enhancement" in addition to the electromagnetic effect. Although difficult to measure accurately, the magnitude of this effect rarely exceeds a factor of 10 and is best thought to arise from the modification of the Raman polarizability tensor of the adsorbate resulting from the formation of a complex between the adsorbate and the metal. Rather than an enhancement mechanism, the chemical effect is more logically to be regarded as a change in the nature and identity of the adsorbate.

5,005 citations


Journal ArticleDOI
TL;DR: In this paper, the first experimental measurements of the temperature distribution along silica-based optical fibres using a semiconductor laser source and an avalanche photodiode detector were reported.
Abstract: The letter reports on the first experimental measurements of the temperature distribution along silica-based optical fibres using a semiconductor laser source and an avalanche photodiode detector. Previous results by the same authors demonstrated the first use of the Raman scattering technique, but used a less practical ion laser source and a photomultiplier detector.

556 citations


Journal ArticleDOI
TL;DR: In this article, it was shown that "impulsive" stimulated Raman scattering (ISRS) should occur, with no laser intensity threshold, when a sufficiently short laser pulse passes through many types of matter.
Abstract: It is shown that ‘‘impulsive’’ stimulated Raman scattering (ISRS) should occur, with no laser intensity threshold, when a sufficiently short laser pulse passes through many types of matter. ISRS excitation of coherent optic phonons, molecular vibrations, and other excitations (including rotational, electronic, and spin) may play important roles in femtosecond pulse interactions with molecules, crystals, glasses (including optical fibers), semiconductors, and metals. Spectroscopic applications of ISRS, including time‐resolved spectroscopy of vibrationally distorted molecules and crystals, are discussed.

498 citations


Journal ArticleDOI
TL;DR: The observation of two-dimensional electron systems and enhanced mobilities in Si/Ge strained-layer multilayer structures and the importance of the built-in strain in lowering the conduction band in Si is emphasized.
Abstract: We report the observation of two-dimensional electron systems and enhanced mobilities in Si/${\mathrm{Si}}_{0.5}$${\mathrm{Ge}}_{0.5}$ strained-layer multilayer structures. The built-in strain is measured by phonon Raman spectroscopy. The mobility enhancement depends strongly on the position of the doped region within the layers. The experimental results can be explained in a consistent way when carrier confinement in the Si layer is assumed. The importance of the built-in strain in lowering the conduction band in Si is emphasized.

453 citations


Journal ArticleDOI
TL;DR: Raman scattering studies of a variety of (GaAl)As superlattices grown by molecular-beam epitaxy are presented in this article, where folded acoustic phonons appear as doublets in the Raman spectra.
Abstract: Raman scattering studies of a variety of (GaAl)As superlattices grown by molecular-beam epitaxy are presented. Folded acoustic phonons appear as doublets in the Raman spectra. Their frequencies are accurately predicted by several models, including an approximate solution of an elastic continuum model through a perturbation approach. Scattering intensities of the folded acoustic modes are predicted by a photoelastic continuum model. Calculations on a layered dielectric continuum provide information about anisotropy of optical phonons. Linear-chain model calculations indicate that optical phonons in binary superlattices are largely confined to alternate layers. Peaks in the Raman data are identified with the resulting quantized optic modes. It is shown that Raman scattering has the potential to provide structural information similar to that which can be obtained by x-ray diffraction.

406 citations


Book
31 Oct 1985
TL;DR: In this article, Collision-Induced Dipole moments are calculated for the effect of collision-induced dipole moments in a multipole model on the Spectral Spectral Spectrum of Compressed Gases.
Abstract: Section 1: Compressed Gases and the Effect of Density.- A. Far Infrared and Infrared Absorption.- Classical Multipole Models: Comparison with Ab Initio and Experimental Results.- Ab Initio Calculations of Collision Induced Dipole Moments.- A Comparative Study of the Dielectric, Refractive and Kerr Virial Coefficients.- The Infrared and Raman Line Shapes of Pairs of Interacting Molecules.- Collision-Induced Absorption in the Microwave Region.- Collision-Induced Absorption in N2 at Various Temperatures.- Far Infrared Absorption Spectra in Gaseous Methane from 138 to 296 K.- Induced Vibrational Absorption in the Hydrogens.- Simultaneous Transitions in Compressed Gas Mixtures.- Molecular Motions in Dense Fluids from Induced Rotational Spectra.- Intercollisional Interference - Theory and Experiment.- Workshop Report: Infrared Absorption in Compressed Gases.- B. Light Scattering.- Ab Initio and Approximate Calcuations of Collision-Induced Polarizabilities.- Depolarization Ratio of Light Scattered by a Gas of Isotropic Molecules.- Depolarized Interaction Induced Light Scattering Experiments in Argon, Krypton, Xenon.- Interaction Induced Rotational Light Scattering in Molecular Gases.- Workshop Report: Light Scattering in Compressed Gases.- Section 2: Liquids and Liquid State Interactions.- A. Atomic Systems.- Theory of Collision-Induced Light Scattering and Absorption in Dense Rare Gas Fluids.- Calculation of Spectral Moments for Induced Absorption in Liquids.- B. Molecular Systems.- Interaction-Induced Vibrational Spectra in Liquids.- Far Infrared Induced Absorption in Highly Compressed Atomic and Molecular Systems.- Theoretical Interpretation of the Far Infrared Absorption Spectrum in Molecular Liquids: Nitrogen.- Molecular Dynamics Studies of Interaction Induced Absorption and Light Scattering in Diatomic Systems.- Interaction Induced Light Scattering from Tetrahedral Molecules.- Local Fields in Liquids.- Pressure - An Essential Experimental Variable in Spectroscopic Studies of Liquids.- Workshop Report: Liquids and Liquid State Interactions.- Section 3: Solid State, Amorphous, and Ionic Systems.- Study of the Collective Excitations in H2 as Observed in Far Infrared Absorption.- Induced Light Scattering in Disordered Solids.- Infrared Induced Absorption of Nitrogen and Methane Adsorbed in NaA Synthetic Zeolite.- Charge Induced Effects in Solid Tritium and Deuterium.- Workshop Reports: Some Considerations on Spectra Induced by Intermolecular Interactions in Molecular Solids and Amorphous Systems.- Section 4: Induced Transitions in Allowed Spectra.- Collision-Induced Effects in Allowed Infrared and Raman Spectra of Molecular Fluids.- Raman Scattering from Linear Molecules.- The Interference of Molecular and Interaction-Induced Effects in Liquids.- Interaction Induced Spectra of "Large" Molecules in Liquids.- The Infrared Spectrum of HD.- Workshop Report: The Interference of Induced and Allowed Molecular Moments in Liquids.- Section 5: Related Subjects.- Contribution of Bound Dimers, (N2)2, to the Interaction Induced Infrared Spectrum of Nitrogen.- Vibrational Spectral Lineshapes of Charge Transfer Complexes.- Collision-Induced Effects in Planetary Atmospheres.- Time-Domain Separation of Collision Induced and Allowed Raman Spectra.- Collision-Induced Radiative Transitions at Optical Frequencies.- Comments on Hyper-Rayleigh Scattering.- Comments on the Spectra of the Halogens and Halogen Complexes in Solution.- Author index.- Chemical index.

343 citations


Journal ArticleDOI
TL;DR: Stimulated Raman scattering from an individual liquid droplet has been observed and the occurrence of a series of spectrally narrow peaks that are regularly spaced in wavelength is consistent with morphology-dependent resonances of the droplet, which acts as an optical resonator.
Abstract: Stimulated Raman scattering (SRS) from an individual liquid droplet (~30-microm radius) has been observed for H(2)O, D(2)O, and ethanol. The occurrence of a series of spectrally narrow peaks that are regularly spaced in wavelength is consistent with morphology-dependent resonances of the droplet, which acts as an optical resonator. The input intensity required to achieve the SRS threshold for the droplet is considerably less than that for the liquid in an optical cell.

317 citations


Journal ArticleDOI
TL;DR: It is shown that in GaAs-AlAs superlattices the confined longitudinal-optic Raman phonons created via either deformation-potential or Frohlich electron-phonon interaction are different and this effect is demonstrated by comparison of resonance and off-resonance Raman spectra.
Abstract: It is shown that in GaAs-AlAs superlattices the confined longitudinal-optic Raman phonons created via either deformation-potential or Fr\"ohlich electron-phonon interaction are different. This effect is demonstrated by comparison of resonance and off-resonance Raman spectra. Phonons of ${A}_{1}$ symmetry (point group ${D}_{2d}$) dominate in resonance, while ${B}_{2}$ phonons are stronger in the off-resonance case. The resonance profile of the ${A}_{1}$ modes is discussed. We also report the observation of confined transverse-optic phonons under extremely resonant conditions.

311 citations


Journal ArticleDOI
TL;DR: In this article, surface-enhanced Raman spectra of benzene and eight mono substituted benzenes adsorbed at gold electrodes have been examined in order to probe the nature of adsorbate surface bonding for simple aromatic molecules.
Abstract: : Surface-enhanced Raman spectra of benzene and eight mono substituted benzenes adsorbed at gold electrodes have been examined in order to probe the nature of adsorbate-surface bonding for simple aromatic molecules. Benzene appears to adsorb flat via pi adsorbate-surface interactions as evidenced by the significant (20-30/cm) downshifts in the symmetric rig breathing mode (v sub 1) and the absence of other ring modes in the SER spectra. Similar results were obtained using gold surfaces prepared by electroplating or anodic-cathodic potential sweeps in chloride, although much more stable SERS was obtained by using the latter procedure. The ring substituents -CHD3, -CH(CH3)2, -C(CH3)3, - Cl, -Br, -CN, -NO2, -COO(-) and -CHO were chosen so to provide steric perturbations or alternative binding modes to the metal surface. With the alkyl, benzoate, and aldehyde substituents, small yet significant (ca. 5-15/cm) decreases in the v sub 12 and v sub 18a characteristic ring modes along with band broadening were observed upon adsorption, consistent with attachment via the benzene ring; For the halogen substituents, smaller such downshifts were obtained along with the appearance of low-frequency modes associated with halogen-surface vibrations, implicating the role of substituent bonding in the adsorption. For the nitrile and nitro substituents, the ring modes were unaltered in frequency or band shape upon adsorption while intense internal substituent modes were observed.

310 citations


Journal ArticleDOI
TL;DR: Time-dependent spontaneous Raman spectra of optically pumped GaAs have been measured with subpicosecond time resolution and substantial time-dependent changes are observed in the spectra which result from screening of the LO phonons by the free carriers and the relaxation of thefree carriers to the band edges.
Abstract: Time-dependent spontaneous Raman spectra of optically pumped GaAs have been measured with subpicosecond time resolution. When the optically injected carrier density is less than ${10}^{17}$ ${\mathrm{cm}}^{\ensuremath{-}3}$, we temporally resolve the growth of the optically induced nonequilibrium LO-phonon population and deduce an average electron-phonon scattering time of about 165 fs. For higher injected carrier densities, substantial time-dependent changes are observed in the spectra which result from screening of the LO phonons by the free carriers and the relaxation of the free carriers to the band edges.

277 citations


Journal ArticleDOI
TL;DR: The observation of interface phonons by Raman scattering from GaAs-AlAs superlattices are reported, which have frequencies close to the optical phonons of bulk GaAs and AlAs and resonate strongly for laser energies near the confined exciton levels of the GaAs quantum wells.
Abstract: We report the observation of interface phonons by Raman scattering from GaAs-AlAs superlattices. These modes have frequencies close to the optical phonons of bulk GaAs and AlAs and resonate strongly for laser energies near the confined exciton levels of the GaAs quantum wells. The results are analyzed in terms of an electrostatic continuum model. In the long-wavelength limit this theory predicts the phonons of the layered media proposed by Merlin et al.



Journal ArticleDOI
TL;DR: In this paper, the cross sections of the symmetric stretching vibrations of SO4−2 and ClO4− as well as the 918 cm−1 C-C stretching vibration of CH3CN have been determined between 220-640 nm.
Abstract: The Raman scattering cross sections of vibrations of SO4−2, NO3−, ClO4−, and CH3CN have been determined between 220–640 nm. The cross sections of the symmetric stretching vibrations of SO4−2 and ClO4− as well as the 918 cm−1 C–C stretching vibration of CH3CN display almost a ν4 excitation frequency dependence. The intensity of the 2249 cm−1 C≡N stretching vibration increases somewhat faster than ν4, but significantly slower than that which would be expected if a dipole allowed C≡N π→π* transition at ∼150 nm dominated the Raman intensity. The intensity of the NO3− symmetric stretch increases with a frequency dependence close to that expected from an Albrecht A term contribution from the ∼200 nm π→π* transition. The fact that the 981 cm−1 SO4−2, 932 cm−1 ClO4−, and 918 cm−1 CH3CN vibrations show essentially only ν4 intensity dependencies indicates that no particular dipole allowed transition dominates the preresonance Raman intensities. These results suggest that conventional preresonance Raman expressions ...

Journal ArticleDOI
TL;DR: In this paper, the symmetry and energies of all optically active phonon modes in black phosphorous were determined by polarized Raman scattering and infrared reflection spectroscopy at room temperature.

Journal ArticleDOI
TL;DR: The application of Raman and resonance Raman spectroscopies to biochemical problems has developed mainly during the past decade as discussed by the authors, and Carotenoid-shave has proved to be very suitable for studies in Resonant Raman Spectroscopy.
Abstract: The application of Raman and resonance Raman spectroscopies to biochemical problems has developed mainly during the past decade. Among naturally occuring chromophores,carotenoidshave proved to be very suitable for studies in resonance Raman spectroscopy. Vibrational spectra can be obtained at very low concentration (until 108M) even if the chromophore is included in a complex biological medium ; thus a very active research area has been developed. After a brief presentation of resonant Raman spectroscopic properties of carotenoids, free and bound to proteins, a re— view, with some examples is given with special emphasis on two distinct advantages of Raman spectroscopy. Time resolution allows short lived spe— cies to be analysed onthe nanosecond and picosecond time scales. Further— more space resolution enables vibrational spectra of carotenoids to be obtained even from single living cells, circumventing the difficult biochemical purification of these pigments.


Journal ArticleDOI
TL;DR: The intensities of the resonances in the Raman spectrum particularly through the volume averaged internal field intensity are described and it is shown that the internal angle-averaged electric field intensity is localized near, but not confined to, the sphere surface.
Abstract: Structural resonances have been found in the Raman spectra of optically levitated liquid droplets of mixtures of water and glycerol. The observed resonances could be assigned by using the well-known Lorenz-Mie formalism. It was found that for the particular droplet under investigation quite high-order numbers (l = 8,9) of the natural modes of oscillation of a sphere play a dominant role. We describe the intensities of the resonances in the Raman spectrum particularly through the volume averaged internal field intensity. We show further that the internal angle-averaged electric field intensity is localized near, but not confined to, the sphere surface.

Journal ArticleDOI
TL;DR: In this article, the authors used Raman and Fourier Transform Infrared spectroscopy to follow the changes the catalysts underwent during the drying and calcination stages and found that the nature of the surface species depends on the loading, pH of the starting solution and the method of catalyst loading.


Journal ArticleDOI
TL;DR: In this article, the authors describe the hydrolyse de tetramethylorthosilicate, Si(OCH 3 ) 4 en solution dans du methanol ou du formamide.
Abstract: Donnees theoriques et cas de l'hydrolyse de tetramethylorthosilicate, Si(OCH 3 ) 4 en solution dans du methanol ou du formamide

Journal ArticleDOI
TL;DR: In this paper, the microscopic information content of coherent transient Raman measurements is analyzed and it is shown that for short pulses and optically thin samples the Kaiser-Laubereau pulse sequence is the Raman analog of the optical free induction decay, and that the experimental observable contains the same dynamical information as the spontaneous Raman line shape.
Abstract: The microscopic information content of coherent transient Raman measurements is analyzed. It is shown that for short pulses and optically thin samples the Kaiser–Laubereau pulse sequence is the Raman analog of the optical free induction decay, and that the experimental observable contains the same dynamical information as the isotropic, spontaneous Raman line shape. Under these conditions, the experiment therefore cannot be used to selectively measure the homogeneous dephasing time of a system with an inhomogeneously broadened line. The results of our analysis are at variance with the earlier results of Kaiser and Laubereau and the more recent predictions of Oxtoby. However, these experiments, under certain circumstances, may be used to obtain a nonselective line narrowing, as found by Zinth, Polland, Laubereau, and Kaiser. We also consider the situation in which the sample is optically dense, in which case laser depletion must be taken into account. The distinction between saturation of the vibrational transition and depletion of the pump pulse is discussed, and selectivity is shown to arise from the former phenomenon, rather than from the latter. This result is at variance with the predictions of George and Harris. An alternative pulse sequence, the Raman echo, is suggested as a tool to achieve selectivity. A unified theory of the Raman echo is developed, which is valid for a bath with arbitrary time scale and which interpolates between the limits of homogeneous and inhomogeneous line broadening.

Journal ArticleDOI
TL;DR: Raman spectral peak-height intensity ratios of vibrational transitions in the C-H stretching-mode region show that the C(24):SPM-H2O system undergoes two thermal phase transitions centered at 48.5 and 54.5 degrees C, which implies that biological membranes may have lipid domains in which some of the lipid hydrocarbon chains penetrate completely across the entire hydrocarbon width ofThe lipid bilayer.
Abstract: Vibrational Raman spectroscopic experiments have been performed as a function of temperature on aqueous dispersions of synthetic DL-erythro-N-lignoceroylsphingosylphosphocholine [C(24):SPM], a racemic mixture of two highly asymmetric hydrocarbon chain length sphingomyelins. Raman spectral peak-height intensity ratios of vibrational transitions in the C-H stretching-mode region show that the C(24):SPM-H2O system undergoes two thermal phase transitions centered at 48.5 and 54.5 degrees C. Vibrational data for fully hydrated C(24):SPM are compared to those of highly asymmetric phosphatidylcholine dispersions. The Raman data are consistent with the plausible model that the lower temperature transition can be ascribed to the conversion of a mixed interdigitated gel state (gel II) to a partially interdigitated gel state (gel I) and that the higher temperature transition corresponds to a gel I----liquid-crystalline phase transition. The observation of a mixed interdigitated gel state (gel II) at temperatures below 48.5 degrees C implies that biological membranes may have lipid domains in which some of the lipid hydrocarbon chains penetrate completely across the entire hydrocarbon width of the lipid bilayer.

Journal ArticleDOI
TL;DR: The first-order Raman spectrum of diamond has been measured in a diamond-anvil cell up to 27 GPa as discussed by the authors, where the fundamental phonon line varies linearly in pressure with a shift of 2.87
Abstract: The first-order Raman spectrum of diamond has been measured in a diamond-anvil cell up to 27 GPa. The fundamental phonon line varies linearly in pressure with a shift of 2.87 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$/GPa. This line appears to be an excellent pressure-calibration standard as an alternate to the ruby pressure scale.

Journal ArticleDOI
Gottlieb S. Oehrlein1, R. M. Tromp1, J. C. Tsang1, Young H. Lee1, E. J. Petrillo1 
TL;DR: In this paper, a modified, less damaged Si region extends from about 30-50A from the surface to a depth in excess of 250A. Results of Monte Carlo range calculations are reported and compared with the damage depth found experimentally.
Abstract: Silicon surfaces which had been exposed to CF/sub 4//40%H/sub 2/ reactive ion etching have been characterized by x-ray photoelectron emission spectroscopy, He ion channeling, H profiling, and Raman scattering techniques. Plasma exposure of a clean Si surface leads to the deposition of a thin ( about 30-50A thick) C,F containing film. The near-surface region ( about 30-50A) of the Si substrate is heavily disordered (''amorphized''), as found by ion channeling and Raman scattering. A modified, less damaged Si region extends from about 30-50A from the surface to a depth in excess of 250A. This layer contains a high concentration ( about 5 atom percent) of H as shown by hydrogen profiling techniques. From the observation of Si-H and Si-H/sub 2/ vibrational modes by Raman scattering, it has been shown that the H is bonded to the Si lattice. In ion scattering, the extended modified Si layer appears to cause a strongly enhanced background in the energy spectra. Results of Monte Carlo range calculations are reported and compared with the damage depth found experimentally.

Journal ArticleDOI
TL;DR: In this paper, the anomalous resonance Raman effect in trans-polyacetylene is described quantitatively by assuming that the conjugations on the polymer chain are statistically interrupted by defects (particle in the box model).
Abstract: The anomalous resonance Raman effect in trans—polyacetylene is described quantitatively by assuming that the conjugations on the polymer chain are statistically interrupted by defects (particle in the box model). The A-term of the Albrechttheory and the Huckel approximation are used to evaluate the Raman cross section and the optical transition energies and transition moments, respectively. The good agreement with experimental results allowed to determine the distribution function for the defects on the chain. In the second part of the paper the particle in the box model is used to interpret Raman spectra taken during the cis—trans—isomeri— zation, during sample degradation by exposure to air, and during the electrochemical doping process. In the latter case evidence for a reversible order—disorder tran— sition is deduced from the experiments.

Journal ArticleDOI
TL;DR: The Raman spectra of the first-excited electronic state and the nature of the electron-phonon coupling have been investigated in this paper using laser energies near the energies of the absorption edges.

Journal ArticleDOI
TL;DR: In this paper, the Fourier transform infrared spectra of aqueous systems were studied using a diamond anvil cell, and the pressure effects on the vibrational dynamics in these systems were investigated.
Abstract: Raman spectra of aqueous phospholipid bilayers and aqueous micellar solution of surfactants at high pressure have been studied in this laboratory. However, some normal modes in these systems are Raman inactive or weakly active, and most of the normal modes of the methylene chains in these systems are highly dispersed. In order to further understand the pressure effects on the vibrational dynamics in these systems, we have extended our pressure studies to the Fourier transform infrared spectra of these aqueous systems, using a diamond anvil cell.

Patent
11 Sep 1985
TL;DR: In this article, the concentration of multiple polyatomic gases are determined almost simultaneously by Raman scattering, where the gas sample is placed in a sampling cell located in the resonance cavity of a laser and a polarized laser beam having sufficient intensity to produce detectable signals of Raman scattered light is passed through the cell by means of a reflection mirror located parallel to the axis of the laser beam adjacent to and outside the cell.
Abstract: The concentration of multiple polyatomic gases are determined almost simultaneously by Raman scattering The gas sample is placed in a sampling cell located in the resonance cavity of a laser and a polarized laser beam having sufficient intensity to produce detectable signals of Raman scattered light is passed through the cell The scattered light is captured and redirected by means of a reflection mirror located parallel to the axis of the laser beam adjacent to and outside of the cell Signals of both inelastic Raman scattered light and elastic laser scattered light are collected by a collection lens means opposite the reflection mirror and outside the gas cell The collection lens is also parallel to the axis of the laser beam The collected scattered signals are directed onto a laser line rejection filter where the scattered elastic laser signals are filtered out and the inelastic Raman scattered signals are transmitted to come in contact with a rotating filter wheel containing a series of interference filters with each filter being specific to the transmission of one Raman line The Raman lines passing through the rotating filters are sensed sequentially by a single detector means and amplified and converted into digital electrical pulses which are processed and converted into visual readouts indicative of the concentration of each of the polyatomic molecules in the gas being determined

Journal ArticleDOI
TL;DR: In this paper, a complete vibrational study of xerogels of vanadium oxide corresponding to the formula V/sub 2/O/sub 5/ x nH/sub 3/O with n = 1.6, 1.2, 0.4, and 0.3 was performed.