bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vibrational spectra of α‐CaNa2P2O7 · 4H2O, CaNH4NaP2O7 · 3H2O and CdNH4NaP2O7 · 3H2O
Authors: Joe I. Hubert , Aruldhas G. , Keresztury Gabor 
Published: May 2005

AbstractThe IR and Raman spectra of polycrystalline samples of α‐CaNa2P2O7 · 4H2O, CaNH4NaP2O7 · 3H2O and CdNH4NaP2O7 · 3H2O were recorded and analysed. Vibrational bands due to NH4+, P2O74− and H2O are identified. The POP bridge angle is found to be about 129° and the pyrophosphate ion is non‐centrosymmetric. The NH4+ ion is likely to be rotating freely in the componds XNH4NaP2O7 · 3H2O (X = Ca, Cd).
Effect of correlation between electronic and vibrational dephasing processes on Raman band shapes
Authors: Torii Hajime , Tasumi Mitsuo 
Published: May 2005

AbstractA theory for Raman band shapes is developed by using the stochastic model. The correlation between electronic and vibrational dephasing is taken into account explicitly. Raman bands become significantly asymmetric in the case of a strong correlation. The Raman band shape can therefore be used to estimate the extent of correlation between the electronic and vibrational dephasing processes. The fact that Raman bands are usually Lorentzian means that the two dephasing processes are not strongly correlated in many cases. The microscopic aspect of the dephasing processes is discussed.
Chemical effect of chloride ions on SERS in silver sol
Authors: Fu Shi‐You , Zhang Peng‐Xiang 
Published: May 2005

AbstractThe influence of chloride ions on surface enhanced Raman scattering (SERS) and the time dependence of the SERS intensity of p‐aminobenzoic acid (PABA) and pyridine in silver sol were studied. The addition of chloride ions can destroy the equilibrium between the gas‐like and the solid‐like phase adsorption of PABA on the silver surface and causes a transformation of the molecular adsorption state and a reduction in the SERS intensity. The influence of chloride ions on SERS and the time dependence of SERS intensity in PABA—silver sol and pyridine—silver sol mixtures were studied. It was found that, in the same environment, the SERS' intensity of pyridine increases and that of PABA decreases on addition of KCl. The results show that the chemical effect of chloride ions on SERS of PABA and pyridine in silver sol is overwhelming. The results of light absorption of PABA and pyridine in silver sol are consistent with this conclusion.
Raman spectra of LnAl3Cl12 compounds
Authors: Shamir J. , Hake D. , Urland W. 
Published: May 2005

AbstractThe Raman spectra of three LnAl3Cl12 compounds (Ln = Gd, Tb and Dy) were studied and the observed bands are interpreted on the basis of terminal and bridging AlCl bonds and LnCl bonds. The results support the suggestion that the AlCl4 species are of anionic type in association with cationic Ln species.
Raman and infrared spectra, conformational stability, barriers to internal rotation, vibrational assignment and ab initio calculation of bromoacetone
Authors: Durig J. R. , Lin Jie , Phan H. V. 
Published: May 2005

AbstractRaman (3200—10 cm−1) and infrared (3500—20 cm−1) spectra were recorded for gaseous and solid bromoacetone (1‐bromopropan‐2‐one), CH2BrC(O)CH3. Additionally, the Raman spectrum of the liquid was recorded and qualitative depolarization values were obtained. These data were interpreted on the basis that the molecule exists predominantly in a gauche conformation of C1 symmetry (dih ∢ BrCCO = 111.8°) in the vapor. In the liquid a second conformer having a trans structure (bromine atom oriented trans to the methyl group) with Cs point group symmetry is also present, and the trans form is the only conformer present in the annealed solid. From a study of the Raman spectrum of the liquid with variable temperatures the trans conformer was determined to be more stable than the gauche form by 385 ± 61 cm−1 (1.09 ± 0.17 kcal mol−1). A complete vibrational assignment is proposed for both conformers. From ab initio Hartree‐Fock gradient calculations with the 4—31G*/MIDI‐4* basis set, optimized geometries for both the gauche and trans conformers were obtained. Similar calculations were also carried out for fluoroacetone and chloroacetone utilizing the 6—31G* basis set with electron correlation with secondorder perturbation. The conformational stabilities, barriers to internal rotation and observed fundamental vibrational frequencies for both the gauche and trans conformers of bromoacetone are compared with those calculated with the STO‐3G* basis set. The results are discussed and compared with the corresponding quantities obtained for some similar molecules.
Raman spectra of tetragonal lanthanide oxychlorides obtained from polycrystalline and single‐crystal samples
Authors: Del Cul G. D. , Nave S. E. , Begun G. M. , Peterson J. R. 
Published: May 2005

AbstractThe reported Raman spectra of the tetragonal [lead chlorofluoride‐type structure, D‐P4/nmm (ITC No. 129)] lanthanide oxychlorides are inconsistent. Nuclear site symmetry analysis predicts six Raman bands. Five peaks are consistently observed, whereas the sixth remains controversial. Also, two different sets of irreducible representations are reported:

which include the three acoustic modes, A2u{T z} and Eu{Tx, Ty}. The present analysis of the polarized Raman spectra from PrOCI and NdOCI single crystals clearly showed that the correct irreducible representation contains the B2g symmetry. The symmetries of three Raman‐active bands are well determined, a fourth band displays two polarizations and a fifth band has no clear polarization and is assigned Eg by default. The EuOCl Raman spectrum exhibits a weak electronic Raman band which originates in electron‐phonon coupling as a result of the closeness between the vibrational and electronic eigenvalues. The low‐energy band (LaOCl, 67 cm−1; EuOCI, 70 cm−1; and GdOCl, 65 cm−1) and the high‐energy band (525 cm−1 for LaOCl) reported by others for selected lanthanide oxychlorides were not observed in the present work.
Catalytic mechanism of cytochrome c oxidase
Authors: Rousseau Denis L. , Han Sanghwa , Song Sunho , Ching Yuan‐Chin 
Published: May 2005

AbstractThe structures and kinetic properties of intermediates in the reaction of cytochrome c oxidase with oxygen initiated by CO photolysis were elucidated by resonance Raman scattering studies. These studies led to a postulated model for the reaction involving an initial intermediate with properties similar to oxyhemoglobin, a peroxo intermediate, a ferryl intermediate and a hydroxy intermediate. The influence of initiating the reaction by CO photolysis was tested by comparing the resonance Raman spectra of the reaction product at 10 ms with that generated by directly mixing oxygen with the enzyme in the absence of CO. Different final products were found for these two protocols. It is proposed that in the absence of CO two molecules of O2 can bind simultaneously at the binuclear site. For single turnover conditions this prevents the reaction from going to completion. However, under physiological conditions where there is a continuous supply of electrons this second molecule of oxygen at the binuclear site places no restrictions on the catalytic mechanism. Instead, it assures an available supply of oxygen to the catalytic site. A model for the reaction under physiological conditions is postulated.
Raman and kinetic studies of myoglobin structure and dynamics
Authors: Champion P. M. 
Published: May 2005

AbstractResonance Raman spectroscopy is used to analyze the absorption line shapes of myoglobin (Mb), its CO ligated complex (MbCO) and the low‐temperature photoproduct (Mb*, CO). Energetically significant inhomogeneous broadening is detected in the line shapes of the unligated species and a strong coupling to low‐frequency (CO torsional) modes is found for MbCO. These observations lead naturally to a simple model of the protein–heme system and its thermally induced conformational fluctuations. The model is used to analyze the non‐exponential ligand binding, optical line shifts and kinetic holeburning exhibited by (Mb*, CO) at low temperatures. The model makes a specific prediction for the high‐temperature Arrhenius barrier at the heme that is found to be in good agreement with kinetic measurements as a function of temperature near 293 K. It is also found that the geminate phase of ligand rebinding remains non‐exponential even at these higher temperatures and it is shown that this is due to a homogeneous relaxation process (probably involving changes in the distal pocket protein conformation following photolysis) rather than to an inhomogeneous distribution of heme rebinding barriers. Slow distal pocket fluctuation time scales are also revealed by using a two‐pulse photolysis protocol to select kinetically a rapidly rebinding sub‐population of the ensemble. These experiments allow the direct monitoring of the time scales of the large‐scale distal pocket interconversions that average the ‘open’ (A0) and ‘closed’ (A1) states of myoglobin.
Fourier transform Raman spectra of diamond‐like carbon films
Authors: Durig J. R. , Little T. S. , Bist H. D. , Rengen A. , Narayan J. 
Published: May 2005

AbstractFourier transform (FT) Raman spectra (3500–50 cm−1) were recorded for hard diamond‐like carbon (DLC) films deposited on silicon wafer substrates at various temperatures. The observed frequency of the graphitic optic zone center phonon (G) at 1595 cm−1 was found to remain constant with variations in the deposition temperature of the substrate, the excitation wavelength and the laser power. However, the disorder activated optical zone edge phonon (D), observed in the 1380–1250 cm−1 region, exhibits changes in the band maximum frequency with the above‐mentioned variables. FT Raman spectroscopy, applied to these films, is shown to be a useful probe for the identification of various different types of diamond‐like structures which are present.
Absorption, resonance Raman and resonance CARS investigations on the permanganate ion doped in potassium perchlorate single crystals at low temperatures
Authors: Leuchs M. , Materny A. , Göttges D. , Schaschek K. , Kiefer W. 
Published: May 2005

AbstractSolid‐state absorption, resonance Raman and resonance CARS spectroscopy were applied to investigate the vibronic properties of the permanganate ion doped in KClO4 single crystals. Experiments were performed for all three types of spectroscopy at 15 K. At this temperature the vibronic structure in the absorption spectrum is highly resolved, allowing detailed studies of resonance Raman and resonance CARS spectroscopy. Selected experimental results are presented.
Resonance Raman spectra of the S3 molecule in sulphur vapour
Authors: Picquenard E. , El Jaroudi O. , Corset J. 
Published: May 2005

AbstractSulphur vapour was investigated by Raman spectroscopy using six laser excitation wavelengths located in the electronic absorption band of the S3 molecule (406.7–514.5 nm). With excitation wavelengths close to the S3 λmax (395 nm) the spectra are mainly resonance enhanced. With the excitation located in the S3 electronic absorption band edge the observed resonance Raman spectra are mainly due to the vibrationally excited molecules. Most Raman lines involve transitions between overtone or combination levels of the symmetric stretching (ν1) and symmetric bending (ν2) modes. The comparison of spectra of samples with various 34S contents recorded with various excitation wavelengths enable us to determine the ω10 and ω20 harmonic wavenumbers and the anharmonicity constants x x and x, for 32S3 and 34S3. New assignments are proposed for all Raman lines observed. A valence force field treatment with the calculated geometry rss = 1.988 Å and α = 117° yields force constants ƒr = 3.91 mdyn Å−1 and ƒrr = 0.36 mdyn Å−1. These force constants are compared with those of the parent X2 or X3 molecules (X = O, S, Se or Te).
Analyse Vibrationnelle des Acides gem‐Dimethylglutarique en Solution Aqueuse II—Acide 3,3‐Dimethylglutarique et Ses Sels de Potassium
Authors: Yolou S. , Delarbre J. L. , Bourret E. , Roger J. , Maury L. 
Published: May 2005

AbstractLes spectres Raman et infrarouges de l'acide 3,3‐diméthylglutarique et de ses sels de potassium en solution aqueuse (H2O et D2O) ont été enregistrés de 200 à 4000 cm−1. L'analyse de l'état de polarisation des raies Raman montre que l'acide 3,3‐diméthylglutarique et son sel neutre de potassium appartiennent au groupe de symétrie C2 tandis que le sel acide répond au groupe de symétrie Cs. Une attribution des vibrations fondamentales est proposée.
Surface‐enhanced Raman scattering of Ru(II) homo‐ and heterolytic complexes with 2,2′‐bipyridine and 1,1′‐biisoquinoline in aqueous silver sol
Authors: Zhu Zi‐Ying , Mao Chen , Yang Rui‐Yang , Dai Li‐Xin , Nie Chong‐Shi 
Published: May 2005

AbstractSERS and SERRS spectra in aqueous silver sol for Ru(II) polypyridine complexes with 2,2′‐bipyridine (bpy) and 1,1′‐biisoquinoline (Q) [Ru(bpy), RuQ, Ru(bpy)2Q2+ and Ru(bpy)Q] were observed with 457.9, 488.0, 514.5 and 632.8 nm excitation. The vibrational modes of the conjugated ring system in the 1600–1400 cm−1 region are enhanced by the resonance effect. Some bands in the SERS spectra of the four complexes show remarkably high intensities with longer wavelength excitation. This may be explained by surface selection rules.
Fourier transform Raman spectroscopy of brightly colored commercially available dyestuffs and pigments
Authors: Durig J. R. , Zunic W. M. , Costner T. G. , Guirgis G. A. 
Published: May 2005

AbstractFourier transform (FT) Raman spectroscopy is shown to be a very powerful and valuable technique for the analysis of brightly colored dyestuffs and pigments. The use of a near‐infrared Nd: YAG laser, as opposed to visible lasers used in conventional Raman instrumentation, virtually eliminates fluorescence from the dye, thus allowing high‐quality Raman spectra to be collected. The small amount of sample required and the limited sample preparation involved also make FT Raman spectroscopy attractive when the amount of sample available is limited or when a rapid, reliable analysis is needed. FT Raman spectra along with the complementary FT‐IR spectra of various commercially available dyestuffs and pigments are presented.
Raman scattering study of [N(CD3)4]2ZnCl4 under hydrostatic pressure
Authors: Henocque J. , Hedoux A. , Sauvajol J. L. 
Published: May 2005

AbstractRaman spectra were measured for [N(CD3)4]2ZnCl4 over the pressure range 1–2000 bar. The influence of pressure was studied for the ZnCl4 bending modes and the 24 cm−1 phonon peak. The pressure dependence of these modes was interpreted having regard to the phase transitions predicted by the temperature–pressure diagram. The pressure dependence of all the recorded spectra highlights a critical behaviour at about 500 bar which does not correspond to any phase transition in the diagram. This phenomenon was interpreted by consideration of the modulation characteristics.
Micro‐Raman analysis of thin‐film diamond temperature sensors
Authors: Bhargava S. , Joshi H. , Bist H. D. , Aslam M. 
Published: May 2005

AbstractThin‐film diamond temperature sensor arrays used in harsh aerospace environments were investigated using micro‐Raman spectroscopy. Raman spectra of three of the samples obtained under specific experimental conditions are presented. On annealing a sample, an increase in graphite content and restoration of long‐range order in its lattice are suggested. Additionally, an untreated sample on irradiation with 1064 nm radiation from a low‐power continuous‐wave Nd: YAG laser exhibits an increase in graphite content. Similar irradiation of an annealed sample shows an increase in the graphite content, a decrease in diamond‐like carbon content and the appearance of a band at 1607 cm−1.
Vibrational Raman spectroscopy of polyconjugated organic oligomers and polymers
Authors: Castiglioni C. , Del Zoppo M. , Zerbi G. 
Published: May 2005

AbstractNew classes of polymers and oligomers whose backbone consists of a network of delocalized π electrons have recently been synthesized and show electrical and non‐linear optical properties of great interest for new technologies. The vibrational spectra of these materials show peculiar features which, if properly interpreted, can provide unique structural information. The interpretation of the spectra requires the development of new theoretical tools. The theoretical and experimental aspects of the problem are presented. It is also shown that the nuclear relaxation following the excitation of the electrons by an intense electromagnetic field can be described in terms of the vibrational modes and can be related to the nuclear contributions to the non‐linear optical responses of the material. In this case Raman intensities play a determining role.
Raman study of aqueous HX solutions (X = F, Cl, Br and I) in both liquid and glassy states
Authors: Kanno H. 
Published: May 2005

AbstractRaman spectra of aqueous HX solutions (X = F, Cl, Br and I) were measured in botl: the liquid and glassy states. It is shown that the preresonance Raman effect is the major factor for the intensity increase in the Raman spectra with increase in halide concentration. The general spectral features are essentially the same as those for aqueous LiX solutions when the contributions of oxonium ions are excluded. The Raman bands of oxonium ions were observed better in the Raman spectra of glassy HX solutions.
SER spectra of acridine and acridinium ions in colloidal silver sols. Electrolytes and PH effects
Authors: Lévi G. , Pantigny J. , Marsault J. P. , Aubard J. 
Published: May 2005

AbstractExtensive surface‐enhanced Raman (SER) spectra of acridine and acridinium ions, taken as probes of DNA intercalating agents, were investigated in colloidal silver sols. From comparison of the SER and Fourier transform near‐IR Raman spectra, it is confirmed that acridine is adsorbed on the metal surface via its protonatable nitrogen atom with its plane perpendicular to the surface. The effects of the electrolyte composition of silver sols, the laser excitation wavelengths and the solution pH were carefully investigated. When present in the solution, halide ions increase the SER signal intensity and shift the nitrogen protonation towards high pH values. Moreover, SER spectra of acridinium (AH+) show a higher signal‐to‐noise ratio than those of the neutral species and this is particularly pronounced when halides ions are present in the silver sols. The additional enhancement probably originates from a resonant charge transfer which appears to be more efficient when AH+ species forms an ion pair with halide ions. The pKa of acridine on a silver surface was estimated from titration curves based on the intensity ratios of lines at ca. 1564 and ca. 1584 cm−1, characteristic of the neutral and the protonated species, respectively. The titration curves behave quadratically or linearly according to whether the silver sols do or do not contain halide ions. On the basis of the phenomenological electrochemical model, the pH was found to change more slowly in the double layer than in the bulk solution.
Raman confocal microprobing, imaging and fibre‐optic remote sensing: A further step in molecular analysis
Authors: Barbillat J. , Dhamelincourt P. , Delhaye M. , Da Silva E. 
Published: May 2005

AbstractThis paper reviews some recent developments in Raman instrumentation. The introduction of the confocal design in most Raman spectrometers represents the latest advance in the field of instruments for Raman spectroscopy. It is the basis of new applications in the field of Raman microprobing and improvements in Raman imaging techniques. The basic principle of confocal microscopy is reviewed and its extension to Raman spectroscopy is discussed in terms of improved depth resolution which results in better background discrimination. A new concept of Raman imaging is also presented which benefits from the confocal system and overcomes most of the limitations of direct imaging techniques. A dual fibre‐optic remote analysis scheme is described which has been developed to optimize the collection of the scattered light while minimizing the interference from the optical fibres.
Near‐infrared Fourier transform Raman spectroscopic study of human brain tissues and tumours
Authors: Mizuno A. , Kitajima H. , Kawauchi K. , Muraishi S. , Ozaki Y. 
Published: May 2005

AbstractNon‐destructive examination of human brain tissues and several kinds of brain tumours using near‐infrared (1064 nm) excited Fourier transform (NIR‐FT) Raman spectroscopy is reported. The spectra from normal but edematous grey and white matter were similar to those of normal rat grey and white matter reported previously. The brain tumours investigated (glioma grade II and III, two acoustic neurinomas and central neurocytoma) gave Raman spectra essentially the same as to that of grey matter. Histological examination of glioma grade III revealed extracellular PAS‐positive materials, which have a band at 856 cm−1due to polysaccharides. One of the neurinoma contained a carotenoid which exhibited two resonance Raman peaks at 1157 and 1524 cm−1; another neurinoma did not contain the carotenoid. The appearance of a strong Raman peak at 960 cm−1suggested that the central neurocytoma of choroid plexus was calcified.
In situ fiber‐optic Raman spectroscopy of organic chemistry in a supercritical water reactor
Authors: Myrick M. L. , Kolis J. , Parsons E. , Chike K. , Lovelace M. , Scrivens W. , Holliday R. , Williams M. 
Published: May 2005

AbstractIn situ measurements were made of several organic chemical reactions in supercritical water using fiber‐optic probes, near‐infrared excitation and CCD array detection. The reactions studied include the conversion of cyclohexene to cyclohexane and benzene in the presence of a platinum catalyst, conversion of cyclohexanol to cyclohexene in the presence of a cobalt catalyst and the homopolymerization of styrene. Transition to the supercritical state was marked by a sudden decrease in the background and the appearance of intense Raman bands for dissolved organic compounds. The results indicate that this method of study is both sensitive and rapid enough to permit kinetic measurements, even when reactions are completed in less than 2 min.
Raman and infrared spectroscopic study of the molecular characterization of the biocompatibility of prosthetic biomaterials
Authors: Bertoluzza A. , Fagnano C. , Tinti A. , Morelli M. A. , Tosi M. R. , Maggi G. , Marchetti P. G. 
Published: May 2005

AbstractRaman spectra were obtained directly in a non‐destructive and non‐invasive way from the biomaterials PMMA [poly(methyl methacrylate)], HDPE (high‐density polyethylene), α‐Al2O3 (alumina) and HA (hydroxyapatite) constituting the components (bone cement, acetabular cup, ball and stem coated with ceramic) of a hip prosthesis. The aim was to give an objective contribution at a molecular level to predict their biocompatibility. In particular, Raman spectra of explanted PMMA bone cements do not show the 1640 cm−1 band due to the stretching mode of CC unsaturated centres. Moreover, conformational changes of PMMA following the implant appear in the spectra in the range 1100‐500 cm−1, where conformational marker bands at 985, 968, 601 and 565 cm−1 are present. The limited number of HDPE explanted acetabular cups did not allow unequivocal Raman results to be obtained by means of band deconvolution in the region between 1500 and 1000 cm−1, regarding the changes in the crystalline, amorphous and interfacial contents of the acetabular cup surfaces following the implant. α‐Al2O3 proved to be a ceramic with good biocompatibility as a biomaterial constituting a hip prosthesis. As regards the stem coating, Raman and Fourier transform IR spectra of HA pre‐coating and HA coating on metal implants show spectroscopic modifications due to structural and chemical changes with formation of other calcium phosphates. The development of new bioactive coatings containing precursors of bone growth and able to promote osteogenesis is outlined.