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Infrared Spectra (infrared + spectrum)
Kinds of Infrared Spectra Selected AbstractsPassport Examination by Polarized Infrared SpectraJOURNAL OF FORENSIC SCIENCES, Issue 4 2007Shigeru Sugawara M.S. Abstract:, In this study, a new nondestructive technique for passport examination is proposed. In this technique, linearly polarized light is used to measure Fourier transform infrared (FT-IR) reflectance spectra of films on the biographical data page. Thirty genuine and thirty-five counterfeit Japanese passports and five marketed films pasted on name cards were examined. The measured spectra were analyzed as follows. The absorption spectra were obtained by the Kramers,Kronig transformations of reflectance spectra. The peak ratios were then calculated from the absorption spectra by adding the peak areas at 1126 and 1263 cm,1 and dividing the result by the peak area at 1727 cm,1. When nonpolarized light was used, the samples could not be distinguished by comparing the peak ratios. However, when polarized light was used, they were successfully distinguished by the comparison. Therefore, polarized light is useful for the forensic discrimination of passport films by the measurement of FT-IR spectra. [source] Infrared Spectra of U.S. Automobile Original Finishes.JOURNAL OF FORENSIC SCIENCES, Issue 3 2006ABSTRACT: The identification, analysis, and occurrence in U.S. automobile original finishes (1974,1989) of Nickel Titanate (yellow) and Chrome Titanate (yellow,orange) are described in this report. The titanate pigments are based on the rutile (titanium dioxide) structure and there are only minor differences between the infrared absorptions of rutile and the titanates. Titanate pigment absorptions in paint spectra can thus be easily mistaken for those of rutile. Each of the titanates, however, contains two elements in addition to titanium that can serve to distinguish them using elemental analyses. Fourier transform infrared (4000,220 cm,1) and X-ray fluorescence instruments were used in combination for the in situ analysis of the titanates. In addition to titanium, nickel, and antimony, the three main detectable elements comprising Nickel Titanate, all of the commercial products of this pigment that were examined also contained impurities of zirconium, niobium, and usually lead. These elements were also detected in most of the monocoats in which Nickel Titanate was identified, as well as in the Chrome Titanate pigments, and the zirconium to niobium ratio was found to exhibit a wide variation. Nickel Titanate is a relatively common pigment that was identified in nearly three dozen U.S. automobile yellow nonmetallic monocoats (1974,1989), while Chrome Titanate appears to have been used in only a few yellow and orange nonmetallic monocoats. The use of the titanate pigments likely increased after this time period as they were replacements for lead chromate pigments (last used in a U.S. automobile original finish in the early 1990s), and are more amenable for use in basecoat/clearcoat finishes than in monocoats. Minor distortions of the infrared absorptions of rutile, anatase, and the titanates obtained using accessories with diamond windows were noted, and their origins are discussed. [source] ChemInform Abstract: Reactions of Uranium Atoms with Ammonia: Infrared Spectra and Quasi-Relativistic Calculations of the U:NH3, H2N,UH, and HN=UH2 Complexes.CHEMINFORM, Issue 4 2009Xuefeng Wang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Infrared Spectra and Theoretical Calculations of KH and (KH)2 in Solid Hydrogen.CHEMINFORM, Issue 10 2008Xuefeng Wang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Infrared Spectra and Structures of the Coinage Metal Dihydroxide Molecules.CHEMINFORM, Issue 6 2006Xuefeng Wang Abstract For Abstract see ChemInform Abstract in Full Text. [source] Infrared Spectra and Structures of the Th(OH)2 and Th(OH)4 Molecules.CHEMINFORM, Issue 4 2006Xuefeng Wang Abstract For Abstract see ChemInform Abstract in Full Text. [source] Structures and Infrared Spectra of Fluoride,Hydrogen Sulfide Clusters from ab initio Calculations: F - -(H2S)n, n = 1,5CHEMINFORM, Issue 3 2006D. A. Wild Abstract For Abstract see ChemInform Abstract in Full Text. [source] Matrix Infrared Spectra and Density Functional Theory Calculations of Molybdenum Hydrides.CHEMINFORM, Issue 51 2005Xuefeng Wang No abstract is available for this article. [source] Infrared Spectra of M(OH)1,2,4 (M: Pb, Sn) in Solid Argon.CHEMINFORM, Issue 50 2005Xuefeng Wang No abstract is available for this article. [source] Infrared Spectra of the Group 2 Metal Dihydroxide Molecules.CHEMINFORM, Issue 11 2005Lester Andrews No abstract is available for this article. [source] Infrared Spectra of Hydrogen-Bonded Ionic Crystals: Ab initio Study of Mg(OH)2 and ,-Be(OH)2.CHEMINFORM, Issue 45 2004Piero Ugliengo Abstract For Abstract see ChemInform Abstract in Full Text. [source] Infrared Spectra of Thallium Hydrides in Solid Neon, Hydrogen, and Argon.CHEMINFORM, Issue 24 2004Xuefeng Wang No abstract is available for this article. [source] Infrared Spectra and DFT Calculations for the Coinage Metal Hydrides MH, (H2)MH, MH2, M2H, M2H - , and (H2)CuHCu in Solid Argon, Neon, and Hydrogen.CHEMINFORM, Issue 1 2004Xuefeng Wang No abstract is available for this article. [source] Infrared Spectra and Structures of the Stable CuH - 2, AgH - 2, AuH - 2, and AuH - 4 Anions and the AuH2 Molecule.CHEMINFORM, Issue 52 2003Lester Andrews Abstract For Abstract see ChemInform Abstract in Full Text. [source] Infrared Spectra of Aluminum Hydrides in Solid Hydrogen: Al2H4 and Al2H6.CHEMINFORM, Issue 41 2003Xuefeng Wang Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Infrared Spectra of the Novel Ge2H2 and Ge2H4 Species and the Reactive GeH1,2,3 Intermediates in Solid Neon, Deuterium and Argon.CHEMINFORM, Issue 37 2002Xuefeng Wang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Reactions of Th and U Atoms with C2H2: Infrared Spectra and Relativistic Calculations of the Metallacyclopropene, Actinide Insertion, and Ethynyl ProductsCHEMISTRY - A EUROPEAN JOURNAL, Issue 32 2006Lester Andrews Prof. Dr. Abstract Reactions of laser-ablated Th and U atoms with C2H2 during condensation with excess argon at 7 K give several new product species. The metallacyclopropene, inserted hydride, and actinide ethynyl are identified from isotopic frequencies and relativistic DFT calculations. The higher-energy vinylidine isomer was not observed. These actinide metallacyclopropenes exhibit substantially stronger bonding interactions than found recently for the Pd and Pt metals. In the case of Th(C2H2) the argon matrix interaction is strong enough to reverse the computed order of states (MR-CISD) in favor of a triplet ground state for the (Ar)n(Th(C2H2)) complex. The nature of the electronic interactions between various metal atoms and acetylene is compared and the origin of the particularly strong interaction for U and Th is traced to the higher energy of their 6d orbitals. The ThCCH and UCCH actinide ethynyl products are also observed and characterized by CC stretching modes 38±2 cm,1 lower than acetylene itself. [source] Infrared Spectra of Protonated Uracil, Thymine and CytosineCHEMPHYSCHEM, Issue 15 2007Jean-Yves Salpin Dr. Abstract The gas-phase structures of protonated uracil, thymine, and cytosine are probed by using mid-infrared multiple-photon dissociation (IRMPD) spectroscopy performed at the Free Electron Laser facility of the Centre Laser Infrarouge d,Orsay (CLIO), France. Experimental infrared (IR) spectra are recorded for ions that were generated by electrospray ionization, isolated, and then irradiated in a quadrupole ion trap; the results are compared to the calculated infrared absorption spectra of the different low-lying isomers (computed at the B3LYP/6-31++G(d,p) level). For each protonated base, the global energy minimum corresponds to an enolic tautomer, whose infrared absorption spectrum matched very well with the experimental IRMPD spectrum, with the exception of a very weak IRMPD signal observed at about 1800 cm,1 in the case of the three protonated bases. This signal is likely to be the signature of the second-energy-lying oxo tautomer. We thus conclude that within our experimental conditions, two tautomeric ions are formed which coexist in the quadrupole ion trap. [source] Infrared Spectrum and Structure of the Hf(OH)4 Molecule.CHEMINFORM, Issue 49 2005Xuefeng Wang Abstract For Abstract see ChemInform Abstract in Full Text. [source] Infrared Spectrum and Structure of the Gold Dihydroxide Molecule.CHEMINFORM, Issue 45 2005Xuefeng Wang Abstract For Abstract see ChemInform Abstract in Full Text. [source] Infrared Spectrum of Hg(OH)2 in Solid Neon and Argon.CHEMINFORM, Issue 12 2005Xuefeng Wang No abstract is available for this article. [source] ChemInform Abstract: Infrared Spectrum of the Hyponitrite Dianion, N2O22- , Isolated and Insulated from Stabilizing Metal Cations in Solid Neon.CHEMINFORM, Issue 10 2002Lester Andrews Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Millimeter-Wave Spectroscopy, High Resolution Infrared Spectrum, ab initio Calculations, and Molecular Geometry of FPO.CHEMINFORM, Issue 52 2001H. Beckers Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Infrared spectra of water molecule encapsulated inside fullerene studied by instantaneous vibrational analysis,INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 10 2009Kiyoshi Yagi Abstract Instantaneous vibrational analysis (IVA) is proposed for computing the infrared spectrum of dynamically fluctuating system, and applied to a water molecule encapsulated into fullerene (H2O@C60). A molecular dynamics simulation is first carried out to generate an ensemble of configurations averaging the rotational and translational motion of H2O inside fullerene. At each configuration, instantaneous vibrational frequencies of the water molecule are computed by the vibrational configuration interaction method, which are then employed to construct the line-shape of the spectrum. The vibrational spectrum in the OH stretching region is computed at a temperature of 10 and 100 K based on a direct potential energy surface incorporating the electronic structure theory. It is found that the vibrational frequency of the symmetric stretching mode is blue-shifted compared to that of isolated water, whereas that of the asymmetric stretching mode exhibits no shift in average. The relation between IVA and instantaneous normal mode analysis is presented, and their performances are compared. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [source] Evidence of partial unfolding of proteins at the ice/freeze-concentrate interface by infrared microscopyJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 9 2009J. Jeff Schwegman Abstract The goal of this research was to use infrared spectroscopy in combination with a freeze drying stage to gain a better understanding of the mechanism of loss of protein integrity due to the stresses associated with freezing. Infrared spectra were collected in triplicate for the interstitial space between ice crystals and through ice crystals in a partially frozen system. Spectra were collected for lactate dehydrogenase (LDH) and human immune globulin (IgG) both in the presence and absence of an added surfactant (polysorbate 80). Spectra collected in the interstitial space, distant from the surface of ice crystals, were very similar to spectra collected from the initial solution regardless of the presence of a surfactant. Spectra collected through ice crystals, without added surfactant, were significantly different than spectra collected from the initial solution. An increase in bands characteristic of intermolecular ,-sheet structures (main component of aggregates) were present in these spectra. The presence of surfactant in both protein formulations resulted in a decrease in intermolecular ,-sheet signals in spectra of the proteins on the ice crystal surface. Additionally, much of the native state structure of LDH initially lost on the surface of ice crystals returned when surfactant was added to the formulation prior to freezing. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:3239,3246, 2009 [source] Effect of characteristics of compounds on maintenance of an amorphous state in solid dispersion with crospovidoneJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 6 2007Yusuke Shibata Abstract Solid dispersion (SD) of indomethacin with crospovidone (CrosPVP) shows useful characteristics for preparation of dosage forms. This study aimed to determine the types of drugs that could adopt a stable amorphous form in SD. Twenty compounds with various melting points (70,218°C), molecular weights (135,504) and functional groups (amide, amino, carbonyl, hydroxyl, ketone etc.) were prepared in SD with CrosPVP. The CrosPVP SDs were prepared using a mechanical mixing and heating method. Melting point and molecular weight were found to have no influence on the ability of a compound to maintain an amorphous state in SD. All compounds containing hydrogen-bond-donor functional groups existed in an amorphous state in SD for at least 6 months. Infrared spectra suggested an interaction between the functional groups of these compounds and amide carbonyl group of CrosPVP. Compounds without hydrogen-bond-donor groups could not maintain an amorphous state and underwent recrystallization within 1 month. It was suggested that the presence of a hydrogen-bond-donor functional group in a compound is an important factor affecting the stable formation of SD with CrosPVP, which contains a hydrogen-bond acceptor. © 2006 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96:1537,1547, 2007 [source] Influence of substituents on the infrared stretching frequencies of carbonyl group in esters of benzoic acidJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 10 2006Vilve Nummert Abstract Infrared spectra of 25 substituted phenyl esters of benzoic acid C6H5CO2C6H4 -X (XH, 3-Cl, 3-F, 3-CN, 3-NO2, 3-CH3, 3-OH, 3-NH2, 4-Cl, 4-F, 4-NO2, 4-CN, 4-OCH3, 4-CH3, 4-NH2, 2-Cl, 2-F, 2-I, 2-NO2, 2-CF3, 2-CN, 2-CH3, 2-OCH3, 2-N(CH3)2, 2-C(CH3)3), 8 alkyl benzoates C6H5CO2R (XCH3, CH2CH3, CH2Cl, CH2CN, CH2CCH, CH2CH2Cl, CH2CH2OCH3, CH2C6H5), and 22 phenyl esters of substituted benzoic acids X-C6H4CO2C6H5 (X3-Cl, 3-NO2, 3-CH3, 3-N(CH3)2, 4-F, 4-Cl, 4-Br, 4-NO2, 4-CH3, 4-C(CH3)3, 4-OCH3, 4-NH2, 2-Cl, 2-F, 2-Br, 2-I, 2-NO2, 2-CN, 2-CF3, 2-CH3, 2-OCH3, 2-NH2) were recorded in tetrachloromethane in the region of 400,4000,cm,1. Carbonyl stretching frequencies ,CO for meta - and para -substituted phenyl esters of benzoic acid and phenyl esters of meta -substituted benzoic acids were shown to correlate with the substituent constants ,o. The influence of the through resonance effect on ,CO was found to be important in the case of +Rpara substituents in the benzoyl part of phenyl benzoates as well. The carbonyl stretching frequencies of ortho derivatives in phenoxy part were shown to correlate with the inductive substituent constant ,I only. In the benzoyl part of the esters the carbonyl stretching frequencies of cis and trans conformers (relative to the carbonyl group) of ortho derivatives were nicely described by dual parameter equations: (,CO)cis,=,(,CO)o,+,c1,I,+,c3,and (,CO)trans,=,(,CO)o,+,c1,p+,+,c3, (R,=,0.99). The trans isomers of phenyl esters of ortho -substituted benzoic acids showed direct resonance similar to that for para derivatives. The positive steric term found for both the cis and trans conformers could be considered as measure of the steric inhibition of resonance between the phenyl ring and the carboxy-group caused by bulky ortho substituents. The existence of cis/trans conformations was supported by frequency calculations with Density Functional Theory (DFT) method at B3LYP/6-311+G** level for the ortho -substituted benzoates. In the case of alkyl benzoates good correlations of ,CO values were obtained when both the Taft ,* and the steric constants were used. For meta - and para -substituted phenyl benzoates s - trans conformation where the plane of the benzene ring in the benzoyl part of the ester is coplanar with the carbonyl bond plane and the plane of the benzene ring in the phenoxy part is twisted nearly perpendicular relative to the carbonyl bond plane was supported. Copyright © 2006 John Wiley & Sons, Ltd. [source] Infrared intensities of benzene derivatives as a measure of the substituent resonance effectJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 10 2001Karel Palát Jr Abstract Infrared spectra of 39 benzene mono-derivatives were recorded in the region 1000,1800,cm,1 and the intensities of the bands ,16a and ,16b were determined by computer separation. The intensities correlated with the squared resonance substituent constants ,Ro as found by Katritzky and co-workers, but band separation does not represent any essential improvement compared with the earlier simpler technique. With substituents including an NH2 group, there is still an interference with the NH2 scissoring deformation band: in these cases deuteration is more effective than band separation. Several new constants ,Ro were determined spectroscopically for substituents of interest in pharmacology and these constants were also calculated by a quantum chemical model. The latter procedure seems to be most efficient and reasonably reliable for calculating new ,Ro constants; the only problem may be with the conformation in the case of axially unsymmetrical substituents. Copyright © 2001 John Wiley & Sons, Ltd. [source] Vibrational spectroscopic studies, conformations and quantum chemical calculations of 3,3,3-trifluoropropyl- silane and 3,3,3-trifluoropropylsilane- d3,JOURNAL OF RAMAN SPECTROSCOPY, Issue 1-3 2006Peter Klaeboe Abstract Infrared spectra of 3,3,3-trifluoropropylsilane (CF3CH2CH2SiH3) and 3,3,3-trifluoropropylsilane- d3 (CF3 CH2CH2SiD3) were obtained in the vapour, liquid, and crystalline solid phases in the range 4000,50 cm,1. Additional spectra in argon matrices at 5 K were recorded before and after annealing to temperatures 20,34 K. Raman spectra of the compounds as liquids were recorded at various temperatures between 296 and 183 K and spectra of the amorphous and crystalline solids were obtained. The spectra revealed the existence of two conformers (anti and gauche) in the fluid phases and in the matrices. When the two vapours were shock-frozen on a cold finger at 78 K, they turned partly crystalline immediately. After subsequent annealing to 140,150 K, ca 7,9 Raman bands of both molecules present in the liquids vanished in the crystal. Similar variations in intensity were observed in the corresponding infrared spectra before and after annealing. The spectra revealed the existence of one conformer (anti) in the crystal. From Raman intensity variations of three independent pairs of anti and gauche bands between 298 and 173 K for the parent compound, and 298 and 183 K for the deuterated analogue, the values ,confHo(gauche,anti) = 4.1 ± 0.3 kJ mol,1 for the parent compound and the same value for the deuterated species were obtained in the liquid state. Annealing experiments in the matrices show that the gauche bands vanish after annealing, demonstrating that the anti conformer also has the lower energy here and that the barrier to gauche , anti inter-conversion is around 5,6 kJ mol,1. The spectra of both conformers have been interpreted in detail. Ab initio and DFT calculations at the HF/6,311G**, B3LYP/6,311 G** and MP2/6,311 G** levels gave optimized geometries, infrared and Raman intensities and vibrational wavenumbers for the anti and gauche conformers. The conformational enthalpy difference derived from the calculations was between 6.0 and 4.1 kJ mol,1 with anti being the low energy conformer. Copyright © 2006 John Wiley & Sons, Ltd. [source] Toxicity Mode-of-action: Discrimination via Infrared Spectra And Eigenvalues of the Modified Adjacency MatrixMOLECULAR INFORMATICS, Issue 2 2003Anna Pino Abstract Aquatic toxicity can be partitioned into a number of mechanisms of action, the allocation of a given chemical to its particular mode being of fundamental importance for the toxicological risk assessment. We investigated the possibility to automatically allocate each chemical to its putative aquatic toxicity mode-of-action on the basis of the sole chemical physical information. In this paper, we refer to the four mode-of-action classes defined in Hermens' laboratory [1, 2]; the chemical descriptors used were the Infrared spectra and the Burden's Modified Adjacency Matrix Eigenvalues. At odds with Infrared spectrum, the Eigenvalues were able to allocate the chemicals into the different mechanism of action classes via a nonlinear discrimination method (K-nearest neighbours classifier). 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