Showing papers on "Infrared spectroscopy published in 1973"
TL;DR: In this paper, an interpretation of the infrared spectra of surface hydroxyl groups based on crystal structure considerations has been suggested for a large number of oxides, which can be used for the interpretation of spectra for some other functional groups.
310 citations
193 citations
TL;DR: In this article, infrared spectra of CO, CO 2, NO, NO 2, and N 2 O adsorbed on silica supported CuO have been obtained over the temperature range of 30 −250 °C.
150 citations
TL;DR: In this paper, the authors used infrared spectroscopy to observe the surface of a silica supported copper oxide catalyst during the reduction of nitric oxide by carbon monoxide and found that the presence of adsorbed CO, CO2, NO, and N2O as well as CO32− and NO3− structures characterized the degree of oxidation of the catalyst surface.
138 citations
TL;DR: In this article, the infrared spectra of zeolites X and Y were recorded in the hydroxyl stretching region under high resolution conditions, and the spectra were broken down into six different components.
Abstract: The infrared spectra of zeolites X and Y were recorded in the hydroxyl stretching region under high resolution conditions. The samples varied in their Al and proton content. The spectra were broken down into six different components. The selection of this number of components was based on reproducible details appearing in the high resolution spectra. An assignment for the different components is proposed, which considers the four different types of oxygen ions as possible sites for proton location. The narrow band at 3650 cm–1 is assigned to O1—H hydroxyl groups, while the broad and asymmetric band at 3550 cm–1 contains components due to O2—H, O3—H and O4—H groups.
128 citations
TL;DR: In this article, a general theoretical model for the IR spectra of the hydrogen bond was presented, which put on equal footing the Fermi resonance and the coupling between the high and low frequency modes.
128 citations
TL;DR: An infrared spectroscopic study has been carried out on ultrastable zeolites derived from type Y zeolite and on their precursors, and the effect of moisture content on the infrared spectrum has been established as mentioned in this paper, which is interpreted as being due to a structural rearrangement involving silica migration into the vacancies created by the dealumination process.
119 citations
TL;DR: In this paper, the products of cocondensation reactions of Ni and Pd atoms with N2 at 4.2-10'K are investigated by matrix isolation infrared and Raman spectroscopy and are shown to be binary dinitrogen complexes of the form of Ni(N2), and pd(n2)m.
Abstract: The products of the cocondensation reactions of Ni and Pd atoms with N2 at 4.2-10'K are investigated by matrix isolation infrared and Raman spectroscopy and are shown to be binary dinitrogen complexes of the form of Ni(N2), and Pd(N2)m. Examination of the reaction products in pure 14N2,in 14N2/15N2, in dilute Ar/14N2, Ar/14N2/15N2 and Ar/14N5N matrices establishes the stoichiometries of the complexes to be respectively n = 1-4 and m = 1-3. Structural assignments can be made for most of the complexes on the basis of infrared and Raman activities and are found to be similar to the analogous carbonyls. Isotopic frequencies and integrated infrared absorption intensities, computed for the NN stretching modes of the individual dinitrogen complexes on the basis of the Cotton-Kraihanzel force field approximation and on isotopic intensity sum rules, are found to be in close agreement with the observed values. Ni(N2)4 in argon is a regular tetrahedral molecule with “end on bonded” dinitrogen. In nitrogen, however, it is slightly distorted. Calculations show that a substitutional site symmetry C2 for Ni(N2) satisfactorily accounts for all of the spectral lines observed for the complex in nitrogen.
111 citations
TL;DR: The strong covalent bonding between Fe and O 2 represents a quite sufficient reason for dioxygen to dissociate from oxyhemoglobin as O 2 rather than O − 2 and relegates the presence or absence of a nonpolar or hydrophobic environment to a minor role.
109 citations
TL;DR: The CO stretching frequency of liquid ethylene and propylene carbonates is higher in the infrared than in the Raman spectrum as mentioned in this paper, which is explained by a coupling between the transition dipoles of neighbouring molecules, made possible by some degree of alignment of molecular dipoles due to the high dipole moment of these molecules.
Abstract: The CO stretching frequency of liquid ethylene and propylene carbonates is higher in the infrared than in the Raman spectrum. The difference amounts to 13 cm–1 for ethylene carbonate at 313 K. This effect is explained as the consequence of a coupling between the transition dipoles of neighbouring molecules, which is made possible by some degree of alignment of molecular dipoles due to the high dipole moment of these molecules (about 16 × 10–30 C m). A study of dilution and temperature effects confirms this interpretation.
TL;DR: The i.r. and Raman spectra of the bismuth oxide halides, including BiOCl, BiOBr, and BiOI, have been recorded over the range 40-600 cm−1.
TL;DR: In this article, the authors reported the single-crystal Raman and i.r. spectra of vanadium(V) oxide and absorption frequencies compared with those calculated using a simple transferred force field.
Abstract: Oriented single-crystal Raman and i.r. spectra of vanadium(V) oxide are reported and absorption frequencies compared with those calculated using a simple transferred force field. It is shown that departures from previously established oxide-group frequencies are due to the relative lightness of the vanadium atom.
TL;DR: In this paper, a theory of two-phonon states appropriate to vibrational excitations in molecular crystals is presented, which includes general values of the wave vector and expressions for the intensity of infrared absorption.
Abstract: A theory of two‐phonon states appropriate to vibrational excitations in molecular crystals is presented. ``Phonon'' is taken to mean any vibrational excitation, external or internal to the molecules of the crystal. The theory includes general values of the wave vector. Possible mechanisms for the interaction of the two‐phonon states with radiation are considered and expressions for the intensity of infrared absorption developed. Experimental results are presented for infrared absorption measurements on thin and thick films of polycrystalline carbon dioxide at low temperature. Transitions involving molecular fundamentals of the major constituent (12CO2) and of isotopic impurities and involving two‐ or multiphonon absorption are observed. The latter include transitions to states involving simultaneous excitation of two internal vibrations as well as excitation of one internal and one lattice vibration. Dispersion curves and densities of states are obtained for two internal molecular fundamentals coupled by ...
TL;DR: In this paper, the stretching modes of several uranium oxide species vaporized from tungsten and iridium Knudsen cells and deposited in argon and krypton matrices have been observed in the 700 −900 cm−1 region of the infrared.
Abstract: Stretching modes of several uranium oxide species vaporized from tungsten and iridium Knudsen cells and deposited in argon and krypton matrices have been observed in the 700–‐900 cm−1 region of the infrared. Studies of the spectra as a function of temperature and composition of the condensed urania together with normal coordinate analyses of the spectra of 16O and 18O‐containing species have led to the following assignments for the 16O species in argon: U16O(ν) = 820.0 cm−1; U16O2(ν3) = 776.1 cm−1, U16O2(ν1) = 765.4 cm−1 (calc). The spectroscopic evidence strongly indicates a linear geometry for UO2. Tentative assignments for the stretching modes of UO3 are also given.
TL;DR: In this paper, it was shown that 1-Aza-adamant-4-one and a number of its derivatives, in which the CO function is modified, show absorption in the near UV region which is attributed to a sigma-coupled transition.
TL;DR: In this article, a number of divalent metal halides with ethylene glycol as the ligands were characterized by means of physical measurements and chemical analyses, and it was shown that the ligand can serve as a bidentate chelating as well as a monodentate coordinating agent.
TL;DR: In this article, the laser Raman and infrared spectra of Li, Na, K, Rb, Cs bicarbonates and carbonates in H2O and D2O have been determined at 25 °C.
Abstract: The laser Raman and infrared spectra of Li, Na, K, Rb, Cs bicarbonates and carbonates in H2O and D2O have been determined at 25 °C. The relative integrated intensities of the Raman bands have been ...
TL;DR: Evidence is presented that the interaction of the uncomplexed antibiotic with polar solvent molecules leads to conformational rearrangements which can be characterized by a step-wise opening of a closed structure stabilized by intramolecular hydrogen bond formation.
Abstract: The 13C nuclear magnetic resonance spectra of the membrane-active antibiotic valinomycin and its alkali-ion complexes are interpreted. From the 13C chemical shifts and infrared absorptions of the highly stable K+, Rb+ and Cs+ complexes in methanol it is concluded that the ligand conformations of these complexes must be similar. The essential features are the coordination of all ester carbonyl groups with the cation in addition to the formation of intramolecular hydrogen bonds between the amide groups. In contrast to these results the weaker Na+ complex of the antibiotic exhibits different spectral properties which are more similar to those of the uncomplexed antibiotic in polar solvents thus indicating the existence of a considerably different ligand conformation in this complex. The structure of the Na+ complex can be characterized by a reduced number of coordinated ester carbonyl groups and intramolecular hydrogen bonds between the amide groups as compared to the complexes with larger cations.
The conformational rearrangements occurring during the complexation of cations are compared to those observed for the uncomplexed valinomycin in solvent systems of different polarities. Evidence is presented that the interaction of the uncomplexed antibiotic with polar solvent molecules leads to conformational rearrangements which can be characterized by a step-wise opening of a closed structure stabilized by intramolecular hydrogen bond formation.
TL;DR: In this article, the i.r.v. spectrum of the complex pentacarbonyliron, [Fe(CO)5], has been recorded in a number of different low-temperature matrices.
Abstract: The i.r. spectrum of the complex pentacarbonyliron, [Fe(CO)5], has been recorded in a number of different low-temperature matrices. U.v. photolysis produces new bands in the C–O stretching region; these bands disappear on exposure to longer-wavelength light and are assigned to the tetracarbonyl fragment [Fe(CO)4] plus carbon monoxide. The fragement probably adopts a C3v structure due to Jahn–Teller distortion of the tetrahedron. In an argon matrix the formation of [Fe(CO)4] becomes irreversible after prolonged photolysis: this is due to diffusion through the solid argon of CO molecules.
TL;DR: In this article, the ground state molecular geometry of CHD 2 CCH was determined from ground state combination differences, from which A 0 values were derived using microwave estimates of B 0 and C 0.
TL;DR: In this article, the infrared spectrum of chemisorbed α-CO on polycrystalline tungsten has been studied using ultrahigh vacuum techniques, and the αCO state has been spectroscopically resolved into two states.
TL;DR: In this article, the authors measured the infrared spectra of CH 3 O(CH 2 CH 2 O-) p CH 3 (p = 1-7) in the crystalline state in the region 4000-400 cm −1.