Transition Moments of Visible Region Absorption Bands oftrans(Cl)-Triammineaquadichlorocobalt(III) Chloride

Nanostructured gold/titania and gold/silica particles with up to 4 wt% Au were made by a single-step process in a spray flame reactor. Gold(III)-chloride hydrate and titania- or silica-based metalorganic precursors were mixed in a liquid fuel solution, keeping concentrations in the flame and overall combustion enthalpy constant. The powders were characterized by x-ray diffraction, transmission electron microscopy, Brunauer–Emmett–Teller, and ultraviolet–visible analysis. The titania or silica specific surface area and the crystalline structure of titania were not affected by the presence of gold in the flame. Furthermore the size of the gold deposits was independent of the metal oxide support (TiO2 or SiO2) and its specific surface area (100 and 320 m2/g, respectively). The gold nanoparticles were nonagglomerated, spherical, mostly single crystalline, and well dispersed on the metal oxide support. Depending on the Au weight fraction (1, 2, and 4 wt%) the Au nanoparticles' mass mean diameter was 3, 7, and 15 nm, respectively, on both titania and silica. The particles showed surface plasmon absorption bands in the ultraviolet–visible region, which is typical for nano-sized gold. This absorption band was red shifted in the case of the titania support, while no shift occurred with the silica support.

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Spectroelectrochemical Study of some μ3-Oxo-μ-acetato Trinuclear Rhodium(III) and Iridium(III) Complexes

Zeitschrift für Naturforschung B ◽

10.1515/znb-1995-0413 ◽

1995 ◽

Vol 50 (4) ◽

pp. 551-557 ◽

Cited By ~ 5

Author(s):

Kenta Takahashi ◽

Keisuke Umakoshi ◽

Akihiro Kikuchi ◽

Yoichi Sasaki ◽

Masato Tominaga ◽

...

Keyword(s):

Absorption Spectrum ◽

Electronic Absorption Spectrum ◽

Absorption Spectra ◽

Electronic Absorption ◽

Electronic Absorption Spectra ◽

Visible Region ◽

Absorption Bands ◽

Visible Absorption ◽

The One ◽

Species Being

New trinuclear rhodium(III) complexes, [Rh3(μ3-O)(μ-CH3COO)6(L)3]+ (L = imidazole (Him), 1-methylimidazole (Meim), and 4-methylpyridine (Mepy)) have been prepared. The Him, Meim, and Mepy complexes show reversible one-electron oxidation waves at E1/2 = +1.12, +1.12, and +1.28 V vs Ag/AgCl, respectively, in acetonitrile. Electronic absorption spectra of the one electron oxidized species of these complexes and [Rh3(μ3-O)(μ-CH3COO)6(py)3]+ (py = pyridine) (E1/2 = +1.32 V ) were obtained by spectroelectrochemical techniques. While the Rh3(III,III,III) states show no strong visible absorption, the Rh3(III,III,IV ) species give a band at ca. 700 nm (ε = 3390-5540 mol dm-3 cm-1). [Ir3(μ3-O)(μ-CH3COO)6(py)3]+ with no strong absorption in the visible region, shows two reversible one-electron oxidation waves at +0.68 and +1.86 V in acetonitrile. The electronic absorption spectrum of the one-electron oxidized species (Ir3(III,III,IV )) also shows some absorption bands (688 nm (ε, 5119), 1093 (2325) and 1400 (ca. 1800)). It is suggested that the oxidation removes an electron from the fully occupied anti-bonding orbital based on metal-dπ-μ3-O-pπ interactions, the absorption bands of the (III,III,IV ) species being assigned to transitions to the anti-bonding orbital.

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Measurements on ultra-violet dichroism

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1955.0044 ◽

1955 ◽

Vol 228 (1173) ◽

pp. 205-219 ◽

Cited By ~ 21

Keyword(s):

Molecular Structure ◽

Single Crystals ◽

Organic Compounds ◽

Crystal And Molecular Structure ◽

Ultra Violet ◽

Peptide Group ◽

Absorption Bands ◽

Transition Moments ◽

Molecular Transition

The dichroism of ultra-violet absorption bands of thin single crystals of some organic compounds has been measured, and the results used to determine the direction of the molecular transition moments of the peptide group and of substituted phenyl groups. Some of the theory of the optics of absorbing crystals has been presented in a form which is useful in interpreting dichroism measurements in terms of crystal and molecular structure.

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Iodine staining as a useful probe for distinguishing amyloid fibril polymorphs

10.1101/2020.03.21.001214 ◽

2020 ◽

Cited By ~ 1

Author(s):

Takato Hiramatsu ◽

Naoki Yamamoto ◽

Seongmin Ha ◽

Yuki Masuda ◽

Mitsuru Yasuda ◽

...

Keyword(s):

Amyloid Fibrils ◽

Visible Region ◽

Structural Diversity ◽

Absorption Bands ◽

Iodine Staining ◽

Titration Curves ◽

Wide Range ◽

Diagnostic Samples ◽

Resonance Raman Spectra ◽

Deep Relationship

ABSTRACTIt is recently suggested that amyloid polymorphism, i.e., structural diversity of amyloid fibrils, has a deep relationship with pathology. However, its prompt recognition is almost halted due to insufficiency of analytical methods for detecting polymorphism of amyloid fibrils sensitively and quickly. Here, we propose that iodine staining, a historically known reaction that was firstly found by Virchow, can be used as a method for distinguishing amyloid polymorphs. When insulin fibrils were prepared and iodine-stained, they exhibited different colors depending on polymorphs. Each of the colors was inherited to daughter fibrils by seeding reactions. The colors were fundamentally represented as a sum of three absorption bands in visible region between 400-750 nm, and the bands showed different titration curves against iodine, suggesting that there are three specific iodine binding sites. The analysis of resonance Raman spectra and polarization microscope suggested that several polyiodide ions composed of I3− and/or I5− were formed on the grooves or the edges of β-sheets. It was concluded that the polyiodide species and conformations formed are sensitive to surface structure of amyloid fibrils, and the resultant differences in color will be useful for detecting polymorphism in a wide range of diagnostic samples.

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Optical Properties of Plasma Dimer Nanoparticles for Solar Energy Absorption

Nanomaterials ◽

10.3390/nano11102722 ◽

2021 ◽

Vol 11 (10) ◽

pp. 2722

Author(s):

Chunlei Sun ◽

Caiyan Qin ◽

Han Zhai ◽

Bin Zhang ◽

Xiaohu Wu

Keyword(s):

Optical Properties ◽

Solar Energy ◽

Energy Absorption ◽

Visible Region ◽

Thermal Conversion ◽

Solar Thermal ◽

Ag Nanoparticle ◽

Absorption Bands ◽

Resonance Band ◽

Conversion Technology

Plasmonic nanofluids have excellent optical properties in solar energy absorption and have been widely studied in solar thermal conversion technology. The absorption of the visible region of solar energy by ordinary metal nanoparticles is usually limited to a narrow resonance band, so it is necessary to enhance the coupling effect of nanoparticles in the visible spectrum region to improve absorption efficiency. However, it is still a difficult task to improve solar energy absorption by adjusting the structure and performance of nanoparticles. In this paper, a plasma dimer Ag nanoparticle is proposed to excite localized surface plasmon resonance (LSPR). Compared with an ordinary Ag nanoparticle in the visible region, the plasmonic Ag dimer nanoparticle produces more absorption peaks and broader absorption bands, which can broaden solar energy absorption. By analyzing the electromagnetic field of the nanoparticle, the resonance mode of the plasma dimer is discussed. The effects of the geometric dimensions of the nanoparticle and the embedding of two spheres on the optical properties are studied. In addition, the effects of a trimer and its special structure on the optical properties are also analyzed. The results show that the proposed plasma dimer Ag nanoparticle has broad prospects for application in solar thermal conversion technology.

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Reflectance Spectra and Some Respiratory Reactions of Bovine, Equine and Human Thrombocytes

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1957.188.2.415 ◽

1957 ◽

Vol 188 (2) ◽

pp. 415-419 ◽

Cited By ~ 5

Author(s):

Charles R. Goucher ◽

W. Kocholaty

Keyword(s):

Cytochrome C ◽

Redox Potential ◽

Cytochrome Oxidase ◽

Sodium Azide ◽

Visible Region ◽

Reflectance Spectra ◽

Absorption Bands ◽

Oxidase System ◽

Chromatic Properties

Reflectance spectra of human, bovine and equine thrombocytes reveal the existence of pigments which absorb in the visible region of the spectrum. The chromatic properties of these pigments change with the redox potential of the cell. These spectra alterations suggest the existence of a cytochrome system, but the position of the absorption bands does not permit their identification with known mammalian cytochromes. However, platelet homogenates contain a cytochrome oxidase which oxidizes mammalian cytochrome c and which is inhibited by sodium azide. Platelet extracts also contain a DPNH oxidase system which is inhibited by sodium azide.

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A New Zinc Phosphate-Tellurite Glass for Magneto-Optical Applications

Nanomaterials ◽

10.3390/nano10091875 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1875

Author(s):

Mihail Elisa ◽

Raluca Constantina Stefan ◽

Ileana Cristina Vasiliu ◽

Stefan Marian Iordache ◽

Ana-Maria Iordache ◽

...

Keyword(s):

Oxygen Vacancies ◽

Tellurite Glass ◽

Zinc Phosphate ◽

Magnetic Measurements ◽

Visible Region ◽

Transmission Band ◽

Optical Measurements ◽

Absorption Bands ◽

Average Molecular Mass ◽

Weak Ferromagnetic

This work investigates the structural, magnetic and magneto-optical properties of a new zinc phosphate-tellurite glass belonging to the 45ZnO-10Al2O3-40P2O5-5TeO2 system. The glass was prepared by a wet method of processing the starting reagents followed by suitable melting–stirring–quenching–annealing steps. Specific parameters such as density, average molecular mass, molar volume, oxygen packaging density, refractive index, molar refractivity, electronic polarizability, reflection loss, optical transmission, band gap and optical basicity have been reported together with thermal, magnetic and magneto-optical characteristics. Absorption bands appear in the blue and red visible region, while over 600 nm the glass becomes more transparent. FTIR and Raman spectra evidenced phosphate-tellurite vibration modes proving the P2O5 and TeO2 network forming role. Magnetic measurements reveal the diamagnetic character of the Te-doped glass with an additional weak ferromagnetic signal, specific to diluted ferromagnetic oxides. Positive Faraday rotation angle with monotonous decreasing value at increasing wavelength was evidenced from magneto-optical measurements. The final product is a composite material comprising of a non-crystalline vitreous phase and Te-based nanoclusters accompanied by oxygen vacancies. The metallic-like Te colloids are responsible for the dark reddish color of the glass whereas the accompanying oxygen vacancies might be responsible for the weak ferromagnetic signal persisting up to room temperature.

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A Fluorescence Study of Hematoporphyrin

Applied Spectroscopy ◽

10.1366/000370273774333137 ◽

1973 ◽

Vol 27 (6) ◽

pp. 444-449 ◽

Cited By ~ 36

Author(s):

R. C. Srivastava ◽

V. D. Anand ◽

W. R. Carper

Keyword(s):

Fluorescence Spectrum ◽

Visible Region ◽

Molecular Association ◽

Polarized Fluorescence ◽

Fluorescence Study ◽

Absorption Bands ◽

Intense Band ◽

Fluorescence Characteristics ◽

Polarization Factor

The fluorescence characteristics of hematoporphyrin have been studied at 26°C as a function of concentration and pH. The pk values are 4.7 and 8.2 as determined in water and water-ethanol mixtures. The fluorescence spectrum consists of a peak at 625 nm and a second, less intense band at 675 nm. These emission bands are assigned to the Qy (0 → 0) and Qx (0 → 0) states. The four absorption bands in the visible region are assigned to π → π* transitions as follows: 502 nm, (1 ← 0); 536 nm, Qy (0 ← 0); 557 nm, Qx (1 ← 0); and 605 nm, Qx (0 ← 0). Corresponding excitation wavelengths include 505,540,570, and 620 nm. Polarized fluorescence is used to establish molecular association as a function of concentration. The polarization factor is used to verify the change from D2h to D4h symmetry as a function of pH.

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Rotational anaylsis of the absorption bands of IC1

Philosophical Transactions of the Royal Society of London. Series A, Containing Papers of a Mathematical or Physical Character ◽

10.1098/rsta.1934.0011 ◽

1933 ◽

Vol 232 (707-720) ◽

pp. 395-430 ◽

Cited By ~ 17

Keyword(s):

Excited States ◽

Complete System ◽

Visible Region ◽

Complete Analysis ◽

High Dispersion ◽

Absorption System ◽

Absorption Bands ◽

Rotational States ◽

Quantum Numbers ◽

Vibrational Constants

The main absorption system of IC1 in the visible region extends from MATHS5730 upwards, and its vibration structure has been studied by various workers. The analysis of this is complete, and the existence of two isotopic molecules, IC135 and IC137, has rendered it possible to determine the vibrational quantum numbers unambiguously. The vibrational constants of the molecule in the normal and excited states have been evaluated, and approximate values of the rotational constants estimated. Precise values of the latter can only be obtained from a fairly complete analysis of the rotation structure. It was known that this would present difficulties, but since some obvious regularities were discernible on preliminary high-dispersion plates, it seemed to be worth attempting. The difficulties arise from two main causes, namely, the relatively high moment of inertia of the molecule, leading to a relatively close spacing of the lines of a branch, and the existence of the two isotope molecules, each giving rise to a complete system. In addition, the vibrational structure is relatively close and high rotational states are developed, with the consequence that successive bands of the same progression always overlap. Since also there are usually several progressions occurring in the same region, it will be realized that the complexity is considerable, and it was important, therefore, to select the most favourable point for the initial attack.

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Ultra-violet and infra-red investigations on muscle

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1950.0024 ◽

1950 ◽

Vol 137 (886) ◽

pp. 80-87 ◽

Cited By ~ 1

Keyword(s):

Absorption Spectrum ◽

Visible Region ◽

Ultra Violet ◽

Muscle Fibres ◽

Absorption Bands ◽

Important Region ◽

Infra Red ◽

New Type ◽

Single Fibres ◽

Red Radiation

Infra-red absorption spectroscopy of muscle has already been carried out, using the Burch reflecting microscope (Barer, Cole & Thompson 1949: Barer, Thompson & Williams unpublished). There are considerable difficulties involved in this type of work. In the first place it is rather doubtful whether such measurements will ever be possible on living muscle owing to the presence of water, which possesses intense absorption bands in some of the most useful regions of the infra-red spectrum. It may be possible to overcome this difficulty to some extent by using heavy water which has a different absorption spectrum. It is in principle possible to obtain information similar to that given by infra-red spectroscopy, even in the presence of water, by means of Raman spectroscopy, but the technical difficulties involved, particularly fight scattering by colloids, would seem to preclude this method of attack so far as muscle is concerned. Our infra-red measurements have hitherto been confined to dried material. The results indicate that there is little prospect of working with whole muscles, as even single isolated striated fibres of the frog, rabbit and crab were usually too thick. However, it was possible to obtain good spectra in the chemically important region from 3 to 14/ µ on exceptionally thin single fibres or on artificially compressed fibres. An attempt was made to detect dichroism by means of polarized infra-red radiation, but to our surprise none was observed throughout the 3 to 14 µ range, even though the material used showed strong birefringence in the visible region. Hr Stocken and I have recently examined certain molecular models of muscle, in the fight of the work of Ambrose, Elliott & Temple (1949) on myosin, and it now appears possible that infra-red dichroism of muscle might be expected to manifest itself only under rather special conditions. We hope to put these theoretical deductions to experimental test. As regards measurements on muscle in the ultra-violet region, the position is much more promising. It is quite possible to determine the absorption spectrum of the A or I band in living single fibres. The entire spectrum from about 230 m µ in the ultra-violet to over 600 m µ , in the visible can be recorded simultaneously, using the reflecting microscope. This technique can also be used with polarized ultra-violet fight, in order to detect variation of dichroism in crystals at different wave-lengths (Barer, Jope & Perutz unpublished), and I intend to apply it to the study of dichroism in muscle fibres. Another new possibility is the observation of birefringence, as well as dichroism, in the ultra-violet. I have recently carried out experiments with a view to developing a new type of ultra-violet polarizer and it should now be possible to use the reflecting microscope as an ultra-violet polarizing microscope.

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