An antenna triplet sensitiser for 1-acyl-7-nitroindolines improves the efficiency of carboxylic acid photoreleaseElectronic supplementary information (ESI) available: Synthetic details for starting materials and photolysis protocols for 4 plus the calculated absorption spectrum for 4, spectra of its progressive photolysis and comparisons of calculated and experimental absorption spectra for 4 and 5. See http://www.rsc.org/suppdata/pp/b3/b316251f/

2004 ◽  
Vol 3 (4) ◽  
pp. 366 ◽  
Author(s):  
George Papageorgiou ◽  
Matthew Lukeman ◽  
Peter Wan ◽  
John E. T. Corrie
Keyword(s):  
Absorption Spectrum ◽  
Carboxylic Acid ◽  
Absorption Spectra ◽  
Supplementary Information ◽  
Calculated Absorption Spectrum ◽  
Experimental Absorption

The absorption spectrum of KBr:Sn2+

1982 ◽  
Vol 60 (5) ◽  
pp. 619-627 ◽  
Author(s):  
A. Scacco ◽  
P. W. M. Jacobs
Keyword(s):  
Absorption Spectrum ◽  
Theoretical Model ◽  
Absorption Spectra ◽  
Cation Vacancy ◽  
Relative Concentration ◽  
Hamiltonian Matrix ◽  
Absorption Bands ◽  
Different Types ◽  
Experimental Absorption ◽  
Good Agreement

Thorough annealing on crystals of KBr.Sn2+ results in significant changes in their absorption spectra. These changes have been interpreted as the effect of the annealing on the relative concentration of different types of Sn2+ centres: isolated Sn2+ substitutional ions ("cubic" centres) and Sn2+–cation vacancy complexes ("tetragonal" and "rhombic" centres). The line shape of the optical absorption has been calculated theoretically, by diagonalizing the complete 12 × 12 Hamiltonian matrix, for cubic centres only, for tetragonal centres only, and for different relative concentrations of cubic and tetragonal centres. The experimental absorption spectra of KBr:Sn2+ crystals that have undergone various annealing treatments are in good agreement with theoretical spectra calculated for appropriate mixtures of the above centres. These results confirm that thorough annealing increases the fraction of isolated Sn2+ substitutional ions at the expense of the Sn2+–cation vacancy complexes. The consistency of the theoretical model is demonstrated by the agreement of the calculated moments of the absorption bands of KBr:Sn2+ with the experimentally derived values.

Some studies in inorganic complexes. XXV. Cobalt(II) and nickel(II) complexes of 2-Acetamidopyridine and 2-Aminomethyl-6-rnethylpyridine, and the cobalt(II) complex of 2-Methylpyridine-6-carboxylic acid

1969 ◽  
Vol 22 (9) ◽  
pp. 1841 ◽  
Author(s):  
KH Shaw ◽  
GJ Sutton
Keyword(s):  
Magnetic Properties ◽  
Carboxylic Acid ◽  
Absorption Spectra ◽  
Infrared Spectra ◽  
Reflectance Spectra ◽  
Inorganic Complexes

Complexes of cobalt(II) and nickel(II) with the ligands 2- acetamidopyridine (acpy) and 2-aminomethyl-6-methylpyridine (mepic) have been prepared and studied. They included [Co(acpy)2X2], [Co(mepic)2X2], [Ni(acpy)2X2], and [Ni-(mepic)2X2], in which X is Cl, Br, I, or NCS; [Co(acpy)2(NO3)2], [Co(mepic)2(NO3)2], [Ni(acpy)2(NO3)2], [Ni(mepic)3NO3]NO3, [Co(acpy)3](ClO4)2, [Co(mepic)3](ClO4)2, [Co(mepic)3](CoCl4), [Ni(acpy)2(H2O)2](ClO4)2, and [Ni(mepic)2(H2O)2](ClO4)2. The inner complex of 2-methylpyridine-6- carboxylic acid [Co(mepiac)2,2H2O)] was also isolated. In all cases, the magnetic properties, conductances, reflectance spectra, absorption spectra, and infrared spectra are in agreement with the concept that they are spin-free, six-coordinate octahedral complexes. The substance [Ni(mepic)2NO3]NO3 contains both bidentate and ionic nitrate.

X-Ray Absorption Fine Structure Study in FeTiO3

1997 ◽  
Vol 11 (16n17) ◽  
pp. 745-748 ◽  
Author(s):  
Rebekah Min-Fang Hsu ◽  
Kai-Jan Lin ◽  
Cheng Tien ◽  
Lin-Yan Jang
Keyword(s):  
Absorption Spectrum ◽  
Fine Structure ◽  
Absorption Spectra ◽  
Mixed Valence ◽  
Structure Study ◽  
X Ray ◽  
Xafs Spectroscopy ◽  
Absorption Fine ◽  
Trivalent State ◽  
X Ray Absorption

X-ray absorption fine structure XAFS spectroscopy has been used to determine the valence system for the Fe atom in ilmenite, FeTiO3 . This is the first XAFS data in FeTiO3 to our knowledge. The α- Fe2O3 data served as the standard in determining the ionization of the Fe atom in FeTiO3 . Observation of intensity and k-space are consistent. There was no evidence of mixed valence on comparing the FeTiO3 near edge X-ray absorption spectrum with α- Fe2O3 data. The absorption spectra suggest that iron is in the trivalent state in ilmenite.

scholarly journals Permittivity spectra and structure of d-bands of germanium telluride, tin telluride and lead telluride

2020 ◽  
pp. 44-49
Author(s):  
D.A. Perevoshchikov ◽  
◽  
V.Val. Sobolev ◽  
A.I. Kalugin ◽  
E.A. Antonov ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Lead Telluride ◽  
Germanium Telluride ◽  
General Behavior ◽  
Electron Transitions ◽  
Tin Telluride ◽  
Experimental Absorption ◽  
Exciton Transitions

Based on the experimental absorption spectra, the permittivity spectra of GeTe, SnTe, and PbTe crystals were obtained in the region of electron transitions from core d -bands of cations. Their specific features and general behavior are revealed. The permittivity spectra of each crystal were decomposed into six elementary components and their main parameters were determined by using of combined Argand diagrams method. Based on the theory of interband and exciton transitions, the nature of the formation of these oscillators was proposed.

Is there any Correlation between the Mobility and the Absorption Spectra of Solvated Electrons in Polar Solvents?

2000 ◽  
Vol 214 (10) ◽  
Author(s):  
P. Krebs
Keyword(s):  
Absorption Spectrum ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Optical Absorption Spectrum ◽  
Chem Phys ◽  
Solvated Electrons ◽  
Polar Solvents ◽  
Excess Electrons

Some years ago Jay-Gerin and Ferradini attempted to establish a correlation between the optical absorption spectrum and the mobility of excess electrons in various polar solvents (J. Chem. Phys.

scholarly journals THE ABSORPTION SPECTRUM OF VISUAL PURPLE

1938 ◽  
Vol 21 (4) ◽  
pp. 411-430 ◽  
Author(s):  
Aurin M. Chase ◽  
Charles Haig
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Light Transmission ◽  
Low Ph ◽  
The Other ◽  
Distilled Water ◽  
Color Purity ◽  
Chemical Combination ◽  
Ph Range ◽  
Sensitive Group

The absorption spectra of visual purple solutions extracted by various means were measured with a sensitive photoelectric spectrophotometer and compared with the classical visual purple absorption spectrum. Hardening the retinas in alum before extraction yielded visual purple solutions of much higher light transmission in the blue and violet, probably because of the removal of light-dispersing substances. Re-extraction indicated that visual purple is more soluble in the extractive than are the other colored retinal components. However, the concentration of the extractive did not affect the color purity of the extraction but did influence the keeping power. This suggests a chemical combination between the extractive and visual purple. The pH of the extractive affected the color purity of the resulting solution. Over the pH range from 5.5 to 10.0, the visual purple color purity was greatest at the low pH. Temperature during extraction was also effective, the color purity being greater the higher the temperature, up to 40°C. Drying and subsequent re-dissolving of visual purple solutions extracted with digitalin freed the solution of some protein impurities and increased its keeping power. Dialysis against distilled water seemed to precipitate visual purple from solution irreversibly. None of the treatments described improved the symmetry of the unbleached visual purple absorption spectrum sufficiently for it to resemble the classical absorption spectrum. Therefore it is very likely that the classical absorption spectrum is that of the light-sensitive group only and that the absorption spectra of our purest unbleached visual purple solutions represent the molecule as a whole.

Effect of intrinsic point defects on ZnO electronic structure and absorption spectra

2020 ◽  
Vol 34 (17) ◽  
pp. 2050147
Author(s):  
Yuqin Guan ◽  
Qingyu Hou ◽  
Danyang Xia
Keyword(s):  
Absorption Spectrum ◽  
Electronic Structure ◽  
Band Gap ◽  
Absorption Spectra ◽  
Point Defects ◽  
Formation Energy ◽  
Stable Structure ◽  
Impurity Level ◽  
Intrinsic Point Defects ◽  
Rich Condition

The effect of intrinsic point defects on the electronic structure and absorption spectra of ZnO was investigated by first-principle calculation. Among the intrinsic point defects in ZnO, oxygen vacancies [Formula: see text] and interstitial zinc [Formula: see text] have the lower formation energy and the more stable structure under zinc(Zn)-rich condition, whereas zinc vacancies [Formula: see text] and interstitial oxygen [Formula: see text] have the lower formation energy and the more stable structure under oxygen(O)-rich condition. The band gap of [Formula: see text] becomes narrow and the absorption spectrum has a redshift. In the visible region, the photo-excited electron transition of [Formula: see text] is graded from the valence band top to the impurity level and then to the conduction band bottom, showing the redshift of absorption spectrum of [Formula: see text] and explaining the reason of [Formula: see text] forming a deep impurity levels in ZnO. Moreover, the impurity energy level of [Formula: see text] coincides with the Fermi level, indicating the significant trap effect and the slow recombination of electrons and holes, which are conducive to the design and preparation of novel ZnO photocatalysts. The band gap of [Formula: see text] and [Formula: see text] broadened and the absorption spectrum showed blueshift, explaining the different values of the ZnO band gap width.

scholarly journals The absorption spectra of halogens and inter-halogen compounds in solution in carbon tetrachloride

1929 ◽  
Vol 124 (795) ◽  
pp. 604-616 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Carbon Tetrachloride ◽  
Absorption Spectra ◽  
Spectroscopic Data ◽  
Chemical Interaction ◽  
Chemical Compounds ◽  
Absorption Bands ◽  
Halogen Compounds ◽  
Inert Solvent ◽  
The Mean

When two solutions are mixed the absorption spectrum of the new solution will be the mean of those of the separate solutions provided that no chemical interaction occures. The mere fact of a departure from additivity does not, however, necessarily denote the formation of true chemical compounds. The solute or solutes may undergo solvation, loosely bound aggregates may occur, and even when marked deviations from the simple law of mixtures are observed it is rarely possible to prove the quantitative formation of a given chemical compound from spectroscopic data alone. The above considerations apply with some force to the problem of the absorption spectra of halogens and inter-halogen compounds in an inert solvent. The three elements show perfectly characteristic absorption bands, they are known to interact with the formation of some quite stable compounds, some relatively stable compounds, and some apparently very unstable compounds.

scholarly journals The absorption spectrum and fluorescence of mercury vapour

1905 ◽  
Vol 76 (512) ◽  
pp. 428-430 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Absorption Coefficient ◽  
Absorption Spectra ◽  
Quartz Glass ◽  
Mercury Vapour ◽  
Blue Colour ◽  
Water Jacket ◽  
Side Tube ◽  
Quartz Spectrograph

Having undertaken the investigation of the absorption spectra of metals in a state of vapour, the first substance examined was mercury, and as the results are interesting I have deemed it advisable to make them a separate communication to the Society. F. P. le Roux describes the vapour of mercury as having a bluish colour, and according to R. J. Strutt, it transmits a feeble steel-blue colour, but the absorption coefficient is small. Experimental.—The substance to be volatilised was contained in a flask of Heraeus’ quartz-glass, with a side tube to the neck from which the metal may be distilled and condensed. To the side tube a water-jacket is fitted through which a constant stream of water may be passed if necessary. The rays from the condensed spark of a pair of lead-cadmium and tin-cadmium electrodes were passed through the flask and on to a cylindrical condensing lens of quartz which focussed the rays on to the slit of a quartz spectrograph.

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