Journal of Raman Spectroscopy

To test the hypothesis that a low concentration of an aqueous solution of Nerium Oleander extract affects the biochemical composition of cancerous cells, Raman spectra of those cells were collected and analyzed for different drug concentrations. The results indicate that Nerium Oleander alters the chemical composition of cancerous cells and can be potentially used as an alternative treatment of prostate cancer.

Raman spectroscopy at low (−100 °C) or high (100–200 °C) temperature is shown to be effective in detecting small amounts of H₂O in CO₂-rich deep lithospheric fluid inclusions, which have previously been thought to be water free.

Raman spectra of jáchymovite, (UO₂)₈(SO₄)(OH)₁₄·13H₂O, were studied, complemented with its infrared spectra, and compared with published Raman and infrared spectra of uranopilite, [(UO₂)₆(SO₄)O₂(OH)₆(H₂O)₆]·6H₂O.

The spectral differences in the Raman spectra of single endospores of six different Bacillus strains that were cultivated on normal nutritient media and media with supplementary divalent manganese as sporulation accelerator were analysed via a micro-Raman setup and subsequent chemometric analysis.

Experimental spectra (Raman and FTIR; protonated and deuterated) as well as DFT calculations (B3-LYP/cc-pVDZ) have been undertaken for three structurally related cyclic peptides exhibiting cis-conformation. Comparisons are made of the cyclic amide I/II bands with their linear counterparts. Band assignments have been made using calculated potential energy distributions.

Protonated and N,O-deuterated Raman spectra in the solid and aqueous solution state, as well as FT-IR spectra (solid state), are reported. DFT calculations (B3-LYP/cc-pVDZ level) suggest a boat conformation for the DKP ring. Aided by normal coordinate analysis, comparisons of the cis amide vibrations of cyclo(L-Asp-L-Asp) are made with those of the trans counterpart.

Experimental Raman (solid/aqueous samples) and FT-IR (solid state) spectra combined with high-level DFT calculations/normal coordinate analyses of protonated/deuterated samples shed light on band assignments for a cyclic peptide. Solid-state samples show characteristic amide I vibrations which are split; the cis amide I band is differentiated by its large deuterium shift of ∼30 cm⁻¹.

Raman spectra of natrouranospinite, were studied, complemented with its IR spectra, and compared with published Raman and infrared spectra of autunite-type minerals.

Understanding wood and other biomass that are heterogeneous natural polymer composites of cellulose, lignin, and hemicellulose will lead to progress in a number of science and technology fields. This paper reports on the use of silver particles to successfully induce the surface-enhanced Raman scattering (SERS) effect in isolated and native state lignins.

The room-temperature ferromagnetism and the Raman spectroscopy data of Cu-doped Zn_1−xCo_xO powders prepared by the sol–gel method are reported. The relative strength of the second-order LO peak to the first-order one in the Raman spectra, which is related to the carrier concentration, of Cu-doped Zn_0.98Co_0.02O powder is strongly correlated with the saturation magnetic moment of the system.

Zinc oxide nanowires coated with a thin film of gold exhibit uniform and repeatable SERS enhancement factor of the order of 10⁶. SERS enhancement shows strong dependence on the thickness of the gold film and the orientation of nanowires on the substrate.

The mixed anion mineral parnauite Cu₉[(OH)₁₀|SO₄|(AsO₄)₂]·7H₂O has been studied by Raman spectroscopy. Characteristic bands associated with arsenate, sulphate and hydroxyl units are identified. A comparison of the Raman spectra with that of other arsenate minerals is made.

Density functional theory calculations and vibrational spectra of 2-bromo 4-chloro phenol and 2-chloro 4-nitro phenol were carried out using B3LYP/6-31 G** basis set. The calculated spectra were obtained from the calculated intensities. The simulated and the experimental spectra agree well.

The normal Raman and surface-enhanced Raman scattering (SERS) spectra of flavanthrone and indanthrone are obtained at several excitation wavelengths. The spectral assignments are aided by density functional calculations. Since both molecules have very high symmetry (C_2h) including a center of inversion, we expect that the modes of u symmetry will be forbidden in the normal Raman spectrum.

Here we report the nature of new di-α-amino (L¹–L³) and α-amino-α-hydroxyphosphinic (L⁴–L⁶) acids non-adsorbed and adsorbed on a colloidal silver surface by means of FT-RS and SERS, respectively. Examining the enhancement, shift in wavenumbers, and changes in breadth of the bands due to the adsorption process, we show that the tilted compounds interact with the colloidal silver substrate mainly through the benzene ring, amino group, and phosphinic moiety.

Here we show that wavenumber shifts in the SERS spectrum can be correlated to specific bonding geometries on metallic surfaces. The relationship between molecular configuration and the specific binding mechanisms inferred from the wavenumber shifts enables us to identify surface geometries of hydroxybenzoic acid isomers adsorbed on metallic surfaces, solely by the SERS spectrum. This method may be implemented to several other molecules adsorbed on metallic surfaces.

We investigated the interfacial structures of various aromatic di-α-amino (L¹–L³) and α-amino-α-hydroxyphosphinic (L⁴–L⁶) acids immobilized onto an electrochemically roughened silver electrode using SERS. These structures were compared to those on a colloidal silver surface to determine the relationship between adsorption strength and geometry.

Raman and IR spectra of formamide (FA) and pyridine (Py) mixtures exhibit two new bands at 996 and 1587 cm⁻¹, which have been assigned to a hydrogen-bonded Py complex. The latter band has been reported for the first time in the literature. In addition, the experimental data on the wavenumber shifts and stoichiometry of the 1:1 FA:Py complex are very well supported by density functional theory (DFT).

New infrared and Raman spectra were measured for the clorotrimethylgermane (CTMG) to complete the assignment for its fundamental modes. The C-H vibrational modes were resolved into their components with the aid of the low-temperature infrared techniques together with the FSD on the Raman spectra.

The spectra were interpreted with the help of normal coordinate analysis (NCA) following full structure optimization and force field calculations based on the density functional theory (DFT) using the standard B3LYP/6-31G** method and basis set combination.

Oxalic acid dihydrate, (COOH)₂ · 2H₂O, is one of the rare examples of a system with strong hydrogen bonding where the acidic OH stretching vibration, that falls below 2000 cm⁻¹, is clearly visible in the Raman spectra.

The experimental and theoretical vibrational spectra of 2-fluorophenylboronic acid (abbreviated as 2fpba) were studied. The Fourier transform Raman and Fourier transform infrared spectra of the 2fpba molecule were recorded in the solid phase. The structural and spectroscopic analysis of the molecule was made by using Hartree-Fock and density functional harmonic calculations. For the title molecule, only one form was found most stable structure by using B3LYP level with the 6-31++G(d,p) basis set. The ¹H and ¹³C nuclear magnetic resonance (NMR) chemical shifts of the 2fpba molecule were calculated using the Gauge-Invariant- atomic Orbital (GIAO) method in DMSO solution using IEF-PCM model and compared with the experimental data.

Raman spectroscopy, ab initio calculations, DSC and TG analysis were combined to investigate the inclusion process of some phenol derivatives with cyclodextrins. In the case of αCD inclusion compounds, unusual stoichiometries were obtained: 1:2 and 2:3 were observed for the meta substituted phenols. The Raman spectra reveal the band splitting of several modes, consistent with the existence of two guest molecules in different chemical environments: included in the CD cavity (A) and outside the cavity (B).

Urethane dimethacrylate (UDMA) and polyhedral oligomeric silsesquioxane (POSS) networks were synthesized using three different types of POSS, two monofunctional POSS (1-propylmethacrylate)-heptaisobutyl substituted (HISO-POSS) and heptacyclopentyl-octasiloxan-1-yloxy) dimethylsilyl] propyl methacrylate (CPENTYL-POSS) and one octafunctional POSS-methacryl substituted (MA-POSS). The cross-linking process was studied by dispersive Raman spectroscopy, showing the influence of temperature, POSS concentration and type against conversion.

Sixteen pottery artefacts restored during the 19th and 20th centuries at the Musée National de Céramique in Sèvres have been analysed. IR and Raman spectra were obtained for all ancient glue residues but among the 16 analysed items, only 7 adhesives have been identified unambiguously and an assignment proposed for 4 others solely on the basis of the Raman signature.

Raman spectra of crystalline salts of carboxylic acids—whewellite and mellite, as well as of aromatic mineral idrilite and amorphous fossil resin were recorded using a portable instrument. All spectra were obtained using 785-nm diode excitation. Obtained results document well that portable Raman instruments can be considered as excellent tools for field geological or exobiological applications.

This article is devoted to the possibility of strong enhancing of Raman signals by Ag or Cu clusters deposited on TiO₂/Ti self-organized nanotubes. It was found that the SERS spectra measured for pyridine adsorbed on the bulk silver substrate were significantly different than the spectra measured on the TiO₂ nanotube/Ti substrates covered with an Ag layer.

We have undertaken a thorough vibrational analysis for 2,4-difluorophenol along with ab initio HF and DFT calculations, due to low toxicity and wide-ranging applications of fluorine derivatives of phenols. The theoretically computed value by B3LYP/6-311G(d,p) level shows at (1) 3711 cm⁻¹ (mode no. 33) due to OH in-plane bending vibration in phenols, and O-H out-of-plane bending vibration (mode no.14) at (2) 780/773 cm⁻¹ by HF and B3LYP method, and shows good agreement with literature as well as experimental observation.

Yellow inorganic pigments in egg yolk tempera were studied to assess the effects of UV-pulsed-laser irradiations. The effects on natural earths could be partially connected to the dehydration of goethite, along with its phase transition to hematite and/or magnetite. Moreover, for all the investigated pigments, laser irradiation induced photochemical modifications in the binding medium.

The vibrational spectroscopic data show that dehydration of erythrocytes results in a change of the heme environment and the formation of a six coordinate low-spin derivative of hemoglobin (Hb), hemi(o)chrome. Whereas fixation of erythrocytes in precipitating fixatives changes Hb to hemichrome, cross-linking fixatives initially maintain Hb in the oxy state but gradually oxidizes it to the met form.

The Fourier transform Raman and infrared spectra of thioguanine have been recorded. Ab initio and density functional computations of the vibrational (IR) spectrum, the molecular geometry, HOMO–LUMO energy gaps and polarizabilities were studied. On the basis of the comparison between calculated and experimental results and the comparison with related molecules, assignments of fundamental vibrational modes are examined. The observed and simulated spectra were found to be well comparable. The electronic transition energies and intensities of spectral lines were carried out using TDDFT and ZINDO methods.

Experimental results indicate that the SiO₂-modified roughened Au substrate can resist the aging in an atmosphere of 50% RH and 20% (v/v) O₂ at 30 °C. Solid and open triangles represent R6G adsorbed on unmodified and modified Au substrates, respectively.

Zn(II) and Cd(II) complexes of a plant metallothionein belonging to the cork oak (Quercus Suber) were undergone to reductive radical stress and analysed by Raman spectroscopy. Sulfur-containing residues resulted to be selectively attacked by radicals and participation of His to metal coordination became necessary for protein stabilization after radical stress. The radical-induced effects were dependent on the divalent metal bound.

This work demonstrates a seed-like ZnO nanostructure that is aggregated with nano-entities using the colloid chemical method. The formation mechanism and optical properties of the ZnO nanostructure are studied. The X-ray diffraction spectrum indicates that the ZnO nanostructures are of polycrystalline pure wurtzite phase. Multiphonon processes in the nanostructure are identified from the Raman scattering spectra in the spectral range 300–2000 cm⁻¹. A strong violet photoluminescence band emission was visible in the room temperature photoluminescence spectra. This work determines the quality of such crystals and extends the optical applications of ZnO nanostructures.

The powder Fourier-transform (FT) infrared (IR) and Raman spectra of the recently characterized NH₄Ag₃(PO₃F)₂ were recorded and are discussed with a site-symmetry analysis based on its known structural data. Some comparisons are made with the solution spectra of the PO₃F²⁻ anion and with those of crystalline Ag₂PO₃F.