Effects of the dielectric constant of the surrounding medium on the plasma-resonance band oscillator strengths of granular films of silver and gold

1982 ◽  
Vol 36 (1) ◽  
pp. 10-13
Author(s):  
I. N. Shklyarevskii ◽  
G. S. Blyashenko
Keyword(s):  
Dielectric Constant ◽  
Surrounding Medium ◽  
Plasma Resonance ◽  
Oscillator Strengths ◽  
Granular Films ◽  
Resonance Band

Effect of non-annealed and annealed ZnO on the optical properties of PVC/ZnO nanocomposite films

2021 ◽  
pp. 089270572110386
Author(s):  
Ali F Al-Shawabkeh ◽  
Ziad M Elimat ◽  
Khaleel N Abushgair
Keyword(s):  
Dielectric Constant ◽  
Refractive Index ◽  
Optical Properties ◽  
Zno Nanoparticles ◽  
Oscillator Strengths ◽  
Nanocomposite Films ◽  
Optical Parameters ◽  
Zno Nanoparticle ◽  
Dispersion Energy ◽  
Optical Susceptibility

The goal of this study was to investigate the optical properties of the prepared polyvinyl chloride (PVC)/zinc oxide (ZnO) nanocomposite films. The PVC/ZnO nanocomposite films consist of the addition of different concentrations with both non-annealed ZnO nanoparticles and ZnO nanoparticles annealed at temperature of 700°C. The PVC/ZnO nanocomposite films by weight concentrations of (0 wt.%, 2.5 wt.%, 5 wt.% and 10 wt.%) have been prepared by the casting method. The optical absorbance and transmittance values of the composites films were measured in the wavelength range between (250 to 1100 nm) at room temperature by using the UV-1800 Shimadzu spectrophotometer. The optical properties (absorption coefficient, dielectric constant, refractive index, and optical conductivity) have been investigated by the ultraviolet (UV) spectrophotometer. The optical parameters (direct optical energy gap, excitation energy for electronic transitions, the dispersion energy, static refractive index, static dielectric constant, optical oscillator strengths, the moments of optical spectrum, linear optical susceptibility, third-order nonlinear optical susceptibility, nonlinear refractive index, high-frequency dielectric constant, the carrier concentration to the effective mass ratio, the long wavelength refractive index and the plasma frequency) were calculated. The results showed that the optical properties behavior of the PVC/ZnO nanocomposite films was found to be dependent on the ZnO concentration, and photon wavelength. In addition, the results of the study show that the optical parameters can be influenced by alter the concentration of the nonannealed and annealed a ZnO nanoparticle in the PVC polymer matrix.

scholarly journals Spectroscopy of Laboratory Plasmas

1972 ◽  
Vol 14 ◽  
pp. 493-527
Author(s):  
D. D. Burgess
Keyword(s):  
Cross Sections ◽  
Surrounding Medium ◽  
Diagnostic Techniques ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Plasma Spectroscopy ◽  
Plasma Diagnostic ◽  
Laboratory Plasma ◽  
Secondary Importance ◽  
Laboratory Plasmas

AbstractWork under the heading of Laboratory Plasma Spectroscopy may be conveniently separated into three classes depending on the extent to which the interaction of the emitting atoms with their plasma environment is central to the investigation. Zero order, the longest established use of laboratory plasmas in connection with astrophysics, concerns the use of hot plasmas for the excitation, measurement, and identification of the spectra of highly-stripped ions. In such work the properties of the plasma itself are usually of secondary importance. In first-order, plasma spectroscopy is used to determine fundamental atomic data concerned with the interaction of an atom with a single particle, usually either a photon or an electron, i.e.: the determination of oscillator strengths and collision cross-sections. Finally, higher-order processes in which the plasma nature of the surrounding medium is most relevant concern the study of line-shapes, and related topics such as the excitation of satellite spectral features by plasma oscillations. Developments in plasma diagnostic techniques in the last five years have greatly extended the scope of the second and third categories and have yielded much astrophysically important information from laboratory studies. Recent advances in these areas are reviewed.

scholarly journals Feasibility Study on Measuring the Particulate Matter Level in the Atmosphere by Means of Yagi–Uda-Like Antennas

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3225 ◽  
Author(s):  
Aarón A. Salas-Sánchez ◽  
Julian Rauch ◽  
M. Elena López-Martín ◽  
J. Antonio Rodríguez-González ◽  
Giorgio Franceschetti ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Simulated Annealing ◽  
Method Of Moments ◽  
Surrounding Medium ◽  
Measurement Procedure ◽  
Characteristic Parameters ◽  
Trade Off ◽  
Promising Solution ◽  
Moderate Length ◽  
Concentration Levels

In this work, the application of a technique for monitoring changes of the dielectric constant of the atmosphere caused by the presence of pollution is discussed. The method is based on changes in the reflection coefficient of the device induced by these dielectric constant variations of the surrounding medium. To that end, several Yagi–Uda-like antenna designs with different size limitations were simulated by using a Method-of-Moments software and optimized by means of a simulated annealing strategy. It has been found that the larger the optimal elements of the array are allowed to be, the higher the sensitivity reached. Thus, in a trade-off between sensitivity and moderate length (regarding flexibility purposes), the most promising solution has been built. This prototype has been experimentally tested in presence of an artificial aerosol made of PAO (polyalphaolefin) oil and black carbon inclusions of a size of 0.2 μm. As a result, potentials for developing a measurement procedure by means of changes in the characteristic parameters of the antenna led by different concentration levels of suspended particles in the surrounding medium are shown. In this manner, a local mapping of polluted levels could be developed in an easy, real-time, and flexible procedure.

scholarly journals E/Z isomerization of astaxanthin and its monoesters in vitro under the exposure to light or heat and in overilluminated Haematococcus pluvialis cells

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yauhen V. Viazau ◽  
Ruslan G. Goncharik ◽  
Irina S. Kulikova ◽  
Evgeny A. Kulikov ◽  
Raif G. Vasilov ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Dielectric Constant ◽  
Incubation Period ◽  
Haematococcus Pluvialis ◽  
Surrounding Medium ◽  
Total Content ◽  
Model System ◽  
Green Algal ◽  
Isomerization Process

AbstractThermo- and photoisomerization of astaxanthin was investigated in a model system (solutions in methanol and chloroform), and the dynamics of astaxanthin isomers and esters content was analyzed in Haematococcus pluvialis green algal cells exposed to factors inducing astaxanthin accumulation. In both systems, the astaxanthin isomerization process seems to be defined by a) the action of light (or heat), and b) the dielectric constant of the surrounding medium. Upon heating, the accumulation of Z-isomers occurred in a model system during the entire incubation period. For the first 5 h of illumination, both Z-isomers accumulated in the solutions up to 5%, and then their content decreased. The accumulated amount of the Z-isomers in the cells of H. pluvialis was found to reach 42% of the total content of astaxanthin initially, and then it decreased during the experiment. The results lead to a conclusion that both cultivation of H. pluvialis culture in specific conditions and heat treatment of the resulting extracts from it might be efficient for obtaining large amounts of economically useful astaxanthin Z-isomer.

scholarly journals Effect of Anderson localization on light emission from gold nanoparticle aggregates

2016 ◽  
Vol 7 ◽  
pp. 2013-2022 ◽  
Author(s):  
Mohamed H Abdellatif ◽  
Marco Salerno ◽  
Gaser N Abdelrasoul ◽  
Ioannis Liakos ◽  
Alice Scarpellini ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Gold Nanoparticle ◽  
Photoelectron Spectroscopy ◽  
Anderson Localization ◽  
Light Emission ◽  
Surrounding Medium ◽  
X Ray ◽  
Photoluminescence Lifetime ◽  
Nanoparticle Aggregates ◽  
Optical Modes

The localization of light known as Anderson localization is a common phenomenon characterizing aggregates of metallic nanostructures. The electromagnetic energy of visible light can be localized inside nanostructures below the diffraction limit by converting the optical modes into nonradiative surface plasmon resonances. The energy of the confined photons is correlated to the size and shape of the nanostructured system. In this work, we studied the photoluminescence dependence of aggregates of 14 nm diameter gold nanoparticles (AuNPs) synthesized by drop-casting a liquid suspension on two different substrates of glass and quartz. The AuNP aggregates were characterized by electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The dielectric constant of the surrounding medium plays a crucial role in determining the aggregate geometry, which affects the Anderson localization of light in the aggregates and hence causes a red-shift in the plasmonic resonance and in the photoluminescence emission. The geometry of the gold nanoparticle aggregates determine the strength of the Anderson localization, and hence, the light emission from the aggregates. The photoluminescence lifetime was found to be dependent on the AuNP aggregate geometry and the dielectric constant of the medium.

Measuring the electronic properties of single-walled carbon nanotubes with adsorbed porphyrins using optical transitions

2010 ◽  
Vol 14 (10) ◽  
pp. 885-890 ◽  
Author(s):  
Gustavo de A.M. Sáfar ◽  
Dayse CarvalhoDa-Silva ◽  
Ynara M. Idemori ◽  
Henrique B. Ribeiro ◽  
Cristiano Fantini ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Dielectric Constant ◽  
Selective Adsorption ◽  
Surrounding Medium ◽  
Single Walled Carbon Nanotubes ◽  
Dielectric Constants ◽  
Single Walled Carbon ◽  
Uv Raman Spectroscopy ◽  
Uv Raman ◽  
Walled Carbon Nanotubes

The dielectric constants of diverse media surrounding single-walled carbon nanotubes (SWCNTs) were probed using photoluminescence (PL) excitation maps of porphyrin/SWCNT aqueous suspensions. The excitation and emission maxima of the nanotubes in these maps were used to probe the dielectric constant variation and doping originated from the porphyrin molecules. The net dielectric constant was calculated for the surrounding medium for each nanotube index and porphyrin isomer. The spread of the dielectric constant values calculated from the data for each (n, m) nanotube chiral index is interpreted on the basis of selective adsorption by each (n, m) nanotube, for each porphyrin isomer. Ultraviolet (UV) Raman spectroscopy corroborates the doping process through the shift of a G band around 1608 cm-1

scholarly journals Study of plasmonic properties of copper monosulfide nanoparticles depending on their dielectric constant

2021 ◽  
Vol 4 (3(60)) ◽  
pp. 9-13
Author(s):  
Iryna Yaremchuk ◽  
Tetiana Bulavinets
Keyword(s):  
Dielectric Constant ◽  
Refractive Index ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Localized Surface Plasmon Resonance ◽  
Surrounding Medium ◽  
Localized Surface Plasmon ◽  
Surface Plasmon Resonance Peak ◽  
Plasmon Resonance Peak

The object of research is plasmonic properties copper of monosulfide nanoparticles. One of the most problematic areas is that there is still no unambiguous answer to which main copper monosulfide nanoparticles parameters have a decisive effect on their resonance absorption, scattering or electric field enhancement. It is necessary to study the plasmonic properties of copper monosulfide nanoparticles depending on their main parameter, namely the dielectric constant. The principle of dipole equivalence and Mee-Gans theory for the modeling of the optical nanoparticle characteristics is used. It is found that dielectric constant is a crucial parameter determining the resulting optical response of such nanoparticles. The surrounding medium refractive index affects the position and magnitude of the nanoparticles maximum plasmonic absorption. The nonspherical nanoparticles are characterized by two plasmon peaks corresponding to transverse and longitudinal localized surface plasmon resonance if the ratio between the axes is higher than 1.5. The ellipsoidal nanoparticles exhibit higher sensitivity to changes in the refractive index of the surrounding medium in comparison to the spherical ones. The obtained research results are primarily the basis for further comprehensive research of plasmonic copper monosulfide nanoparticles for their specialized applications. Second, knowledge of the influence of the nanoparticle dielectric constant on their resulting spectral characteristics allow tuning of the localized surface plasmon resonance peak position in a wide wavelength range, from 500 to 1200 nm, using the nanoparticle synthesis technique. Thus, the material under study is promising for sensor applications in a wide spectral range.

Oscillator Strength Measurements in the Vacuum-Ultraviolet by the Emission Method

1988 ◽  
Vol 102 ◽  
pp. 353-356
Author(s):  
C. Goldbach ◽  
G. Nollez
Keyword(s):  
Oscillator Strength ◽  
Vacuum Ultraviolet ◽  
Oscillator Strengths ◽  
Emission Method ◽  
Absolute Scale ◽  
Good Agreement

AbstractThe principles and the realization of an experiment devoted to oscillator strength measurements in the vacuum-ultraviolet by the emission method are briefly presented. The results obtained for the strong multiplets of neutral nitrogen and carbon in the 1200-2000 Å range yield an absolute scale of oscillator strengths in good agreement with the most recent calculations.

Sign in / Sign up

Export Citation Format

Share Document