scholarly journals Тип оптических переходов на краю фундаментального поглощения кристаллов TlGaSe-=SUB=-2-=/SUB=- и TInS-=SUB=-2-=/SUB=-, подвергнутых γ-облучению

2019 ◽  
Vol 127 (9) ◽  
pp. 420
Author(s):  
Р.М. Сардарлы ◽  
Ф.Т. Салманов ◽  
Н.А. Алиева
Keyword(s):  
Optical Properties ◽  
Radiation Dose ◽  
Optical Absorption ◽  
Gamma Irradiation ◽  
Single Crystals ◽  
Irradiation Dose ◽  
Optical Transitions ◽  
Optical Absorption Spectra ◽  
Interband Transitions ◽  
Before And After

The effect of gamma irradiation on the optical properties of layered TlGaSe2 and TlInS2 crystals in the wavelength range of 400–1,100 nm at 300 K is studied. From the analysis of optical absorption spectra, the energies of direct and indirect optical interband transitions before and after gamma irradiation are determined. It is shown that as the gamma-irradiation dose is accumulated in the range of 0–25 Mrad by TlGaSe2 and TlInS2 single crystals, the energies of direct and indirect allowed optical transitions increase from Egd = 2.06 eV and Egi = 1.90 eV at D = 0 Mrad to Egd = 2.11 eV and Egi = 1.98 eV at D = 25 Mrad for TlGaSe2 and Egd = 2.32 eV crystals and Egi = 2.27 eV at D = 0 Mrad to Egd = 2.35 and Egi = 2.32 eV at D = 25 Mrad for TlInS2 crystals. A decrease in the transmittance at doses from 0 to 5 Mrad and a further increase in the transmittance at the radiation dose D = 25 Mrad are observed.

Preparation and Properties of Co/SiO2 and Co3O4/SiO2 Composites

1990 ◽  
Vol 195 ◽  
Author(s):  
W. Win ◽  
E. M. Logothetis ◽  
R. E. Soltis ◽  
H. K. Plummer ◽  
L. E. Wenger
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Optical Absorption Spectra ◽  
Interband Transitions ◽  
Uniform Size

ABSTRACTFilms of Co/SiO2 composites were prepared by sequential sputtering from Co and SiO2 targets in Ar. As-grown films as well as films annealed in H2/N2 atmospheres consist of hcp Co particles of uniform size embedded in the SiO2 matrix. The measured optical absorption spectra of these composites are consistent with the Maxwell-Garnett theory except for the absence of the predicted structure that arises from the interband transitions of cobalt. Composites consisting of semiconducting Co3 O4 particles embedded in SiO2 were prepared by post-growth annealing of Co/SiO2 films in air. The optical properties of these composites were found to be comparable to those of CO3O4.

Effects of Gamma Irradiation on Optical Properties of Colloidal Nanocrystals

2007 ◽  
Vol 1038 ◽  
Author(s):  
Nathan J Withers ◽  
Krishnaprasad Sankar ◽  
Brian A. Akins ◽  
Tosifa A. Memon ◽  
Jiangjiang Gu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Gamma Irradiation ◽  
Irradiation Dose ◽  
Nanocrystalline Material ◽  
Light Output ◽  
Colloidal Nanocrystals ◽  
Photoluminescence Intensity ◽  
Photoluminescence Properties ◽  
Material Systems ◽  
Dose Radiation

AbstractThe effects of 137Cs gamma irradiation on photoluminescence properties, such as spectra, light output, and lifetime, of several types of colloidal nanocrystals have been investigated. Irradiation-induced damage testing was performed on CdSe/ZnS, LaF3:Eu, LaF3:Ce, ZnO, and PbI2 nanocrystals synthesized on a Schlenk line using appropriate solvents and precursors. Optical degradation of the nanocrystals was evaluated based on the measured dependence of their photoluminescence intensity on the irradiation dose. Radiation hardness varies significantly between various nanocrystalline material systems.

scholarly journals Электронная структура и спектры оптического поглощения золотых фуллеренов Au-=SUB=-16-=/SUB=- и Au-=SUB=-20-=/SUB=-

2019 ◽  
Vol 61 (6) ◽  
pp. 1204
Author(s):  
Г.И. Миронов
Keyword(s):  
Optical Properties ◽  
Energy Spectrum ◽  
Optical Absorption ◽  
Near Infrared ◽  
Fourier Transforms ◽  
Green Functions ◽  
Optical Absorption Spectra ◽  
New Class ◽  
Infrared Spectral ◽  
Neighboring Site

AbstractThe electronic and optical properties of gold fullerenes are studied in the framework of the Hubbard model. The expressions of the Fourier transforms of anticommutator Green functions have been obtained for gold fullerenes Au_16 and Au_20, the poles of which determine the energy spectrum of the system under consideration. The calculations are performed for the thermodynamic means that characterize jumps of electrons from a nanosystem site to a neighboring site, the correlation functions demonstrating the possibility of existing two d electrons with oppositely oriented spin projections on the same site of the fullerenes consisting of gold atoms. The optical absorption spectra are presented. The optical absorption peaks of ions $${\text{Au}}_{{20}}^{ - }$$ and $${\text{Au}}_{{16}}^{ - }$$ correspond to a near-infrared spectral region, where the light absorption by blood or a soft tissue is vanishingly small; thus, these ions can be used as a new class of contrast improvements and phototherapeutic means for diagnostics and treatment of cancer.

scholarly journals Optical properties of size selected neutral Ag clusters: electronic shell structures and the surface plasmon resonance

Nanoscale ◽  
2018 ◽  
Vol 10 (44) ◽  
pp. 20821-20827 ◽  
Author(s):  
Chongqi Yu ◽  
Romain Schira ◽  
Harald Brune ◽  
Bernd von Issendorff ◽  
Franck Rabilloud ◽  
...  
Keyword(s):  
Optical Properties ◽  
Surface Plasmon Resonance ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Shell Structures ◽  
Optical Absorption Spectra ◽  
Electronic Shell ◽  
Ag Clusters

We present optical absorption spectra from the ultraviolet to the visible for size selected neutral Agn clusters (n = 5–120) embedded in solid Ne.

Change in yhe Optical Properties of Sapphire Induced by Ion Implantation

1997 ◽  
Vol 504 ◽  
Author(s):  
D. Ila ◽  
E. K. Williams ◽  
S. Sarkisov ◽  
D. B. Poker ◽  
D. K. Hensley
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Full Width Half Maximum ◽  
Rutherford Backscattering Spectrometry ◽  
Full Width ◽  
Half Maximum ◽  
Transmission Electron ◽  
Before And After ◽  
Linear Optical Properties ◽  
Average Size

ABSTRACTWe have studied the formation of nano-crystals, after implantation of 2.0 MeV gold, 1.5 MeV silver, 160 keV copper and 160 keV tin into single crystal of A12O3. We also studied the change in the linear optical properties of the implanted Al2O3 before and after subsequent annealing by measuring the increase in resonance optical absorption. Applying Doyle's theory and the results obtained from Rutherford backscattering spectrometry (RBS) as well as the full width half maximum of the absorption band from Optical Absorption Photospectrometry (OAP), we measured the average size of the metallic clusters for each sample after heat treatment. The formation and crystallinity of the nanoclusters were also confirmed using transmission electron microscopy (TEM) technique.

Optical Absorption Spectra of Substituted Methylenes Oriented in Single Crystals

1966 ◽  
Vol 44 (1) ◽  
pp. 413-414 ◽  
Author(s):  
Gerhard Closs ◽  
Clyde A. Hutchison ◽  
Bryan E. Kohler
Keyword(s):  
Optical Absorption ◽  
Single Crystals ◽  
Absorption Spectra ◽  
Optical Absorption Spectra
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