scholarly journals Optical Absorption and Photoluminescence in the Spherical InP/InSb/InP Core/ shell/ shell Nano Structure

2018 ◽  
Vol 2 (1) ◽  
Keyword(s):  
Incident Light ◽  
Energy Levels ◽  
Charge Carriers ◽  
Oscillator Strengths ◽  
Core Shell ◽  
Photoluminescence Spectra ◽  
Interband Transitions ◽  
Nano Structure ◽  
Resonant Character ◽  
The One

The one particle states of charge carriers are considered in InP/InSb/InPcore/shell/shell spherical quantum nano structure at the regime of strong quantization. The results of numerical calculations for the values of the energy of charge carriers for different values of the thickness of the quantizing layer of InSb are presented. The calculations were performed with allowance for the Kaned is persion for electrons and light holes in the InSb layer. The dependence of the number and position of the energy levels of charge carriers in the quantizing layer of InSb on the width of the well (layer thickness) is shown. The dependence of the absorption coefficient and photoluminescence spectra on the energy of incident light of interband transitions have been investigated. The oscillator strengths and selection rules for these transitions have been obtained. The absorption has a strictly resonant character. By the orbital and azimuthal numbers only diagonal inter band transitions are possible. For the radial number, the transitions between the states with the same radial numbers have the highest intensity

scholarly journals Extended theoretical transition data in C i–iv

2021 ◽  
Vol 502 (3) ◽  
pp. 3780-3799
Author(s):  
W Li ◽  
A M Amarsi ◽  
A Papoulia ◽  
J Ekman ◽  
P Jönsson
Keyword(s):  
Transition Probabilities ◽  
Energy Levels ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Internal Validation ◽  
Hartree Fock ◽  
Relativistic Configuration ◽  
The Difference ◽  
The One ◽  
Relative Differences

ABSTRACT Accurate atomic data are essential for opacity calculations and for abundance analyses of the Sun and other stars. The aim of this work is to provide accurate and extensive results of energy levels and transition data for C i–iv. The Multiconfiguration Dirac–Hartree–Fock and relativistic configuration interaction methods were used in this work. To improve the quality of the wavefunctions and reduce the relative differences between length and velocity forms for transition data involving high Rydberg states, alternative computational strategies were employed by imposing restrictions on the electron substitutions when constructing the orbital basis for each atom and ion. Transition data, for example, weighted oscillator strengths and transition probabilities, are given for radiative electric dipole (E1) transitions involving levels up to 1s22s22p6s for C i, up to 1s22s27f for C ii, up to 1s22s7f for C iii, and up to 1s28g for C iv. Using the difference between the transition rates in length and velocity gauges as an internal validation, the average uncertainties of all presented E1 transitions are estimated to be 8.05 per cent, 7.20 per cent, 1.77 per cent, and 0.28 per cent, respectively, for C i–iv. Extensive comparisons with available experimental and theoretical results are performed and good agreement is observed for most of the transitions. In addition, the C i data were employed in a re-analysis of the solar carbon abundance. The new transition data give a line-by-line dispersion similar to the one obtained when using transition data that are typically used in stellar spectroscopic applications today.

scholarly journals Синтез и фотолюминесценция наноразмерных структур на основе сульфидов цинка, кадмия и марганца в полиакрилатной матрице

2020 ◽  
Vol 54 (12) ◽  
pp. 1321
Author(s):  
А.А. Исаева ◽  
В.П. Смагин
Keyword(s):  
Optical Radiation ◽  
Energy Levels ◽  
Radiation Energy ◽  
Photoluminescence Excitation ◽  
Photoluminescence Spectra ◽  
Interband Transitions ◽  
Nanoscale Structures ◽  
Semiconductor Structures ◽  
Recombination Processes ◽  
Zinc Cadmium

Photoluminescence of nanoscale structures based on zinc, cadmium and manganese sulfides depending on the conditions of synthesis and doping in the medium (poly)methylmethacrylate (PMMA). Photoluminescence excitation is associated with interband transitions of electrons in the semiconductor structures, absorption of optical radiation energy by defects in the crystal structure, as well as with the transfer of energy to the excited energy levels of Mn2+ ions. Luminescence occurs as a result of recombination processes at the levels of defects in the structure of the surface of particles and 4T1 → 6A1 transitions between the proper energy levels of Mn2+ ions. Based on changes in the photoluminescence spectra and photoluminescence excitation of PMMA/(Zn,Cd,Mn)S compositions, assumptions are made about the structure of particles. It is shown that their photoluminescence is affected by the distribution of Mn2+ ions in the structure of layers and on the surface of particles.

Stress Whitening in Polypropylene. I. Light Scattering Theory and Model Experiments

1995 ◽  
Vol 60 (11) ◽  
pp. 1875-1887 ◽  
Author(s):  
Jaroslav Holoubek ◽  
Miroslav Raab
Keyword(s):  
Refractive Index ◽  
Light Scattering ◽  
Incident Light ◽  
Polymeric Materials ◽  
Wavelength Dependence ◽  
Theoretical Background ◽  
Surrounding Matrix ◽  
Embedded Particles ◽  
The One ◽  
Stress Whitening

Theoretical background for an optical method is presented which makes it possible to distinguish unambiguously between voids and particles as light scattering sites in polymeric materials. Typical dependences of turbidity as a function of diameter of scattering elements, their volume fractions and also turbidity curves as a function of the wavelength of the incident light were calculated, based both on the Lorenz-Mie theory and the fluctuation theory. Such dependences calculated for polypropylene-containing voids on the one hand and particles, differing only slightly from the surrounding matrix in their refractive index, on the other hand, are markedly different. The most significant results are: (i) Turbidity is at least by two orders of magnitude larger for voids in comparison to embedded particles of ethylene-propylene (EPDM) rubber of the same size, concentration and at the same wavelength. (ii) The wavelength dependence of turbidity for EPDM particles and the inherent refractive index fluctuations in the polypropylene matrix is much steeper as compared to voids for all considered diameters (0.1-10 μm). Thus, the nature of stress whitening in complex polymeric materials can be determined from turbidity measurements.

Systematic calculations of energy levels and transitions rates in Mo XXVIII

2020 ◽  
Vol 75 (8) ◽  
pp. 739-747
Author(s):  
Feng Hu ◽  
Yan Sun ◽  
Maofei Mei
Keyword(s):  
Energy Levels ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Data Sets ◽  
Electron Systems ◽  
Excitation Energies ◽  
Experimental Values ◽  
Qed Effects ◽  
Hyperfine Structures ◽  
Good Agreement

AbstractComplete and consistent atomic data, including excitation energies, lifetimes, wavelengths, hyperfine structures, Landé gJ-factors and E1, E2, M1, and M2 line strengths, oscillator strengths, transitions rates are reported for the low-lying 41 levels of Mo XXVIII, belonging to the n = 3 states (1s22s22p6)3s23p3, 3s3p4, and 3s23p23d. High-accuracy calculations have been performed as benchmarks in the request for accurate treatments of relativity, electron correlation, and quantum electrodynamic (QED) effects in multi-valence-electron systems. Comparisons are made between the present two data sets, as well as with the experimental results and the experimentally compiled energy values of the National Institute for Standards and Technology wherever available. The calculated values including core-valence correction are found to be in a good agreement with other theoretical and experimental values. The present results are accurate enough for identification and deblending of emission lines involving the n = 3 levels, and are also useful for modeling and diagnosing plasmas.

scholarly journals Exciton-Related Raman Scattering, Interband Absorption and Photoluminescence in Colloidal Cdse/Cds Core/Shell Quantum Dots Ensemble

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1274
Author(s):  
Grigor A. Mantashian ◽  
Paytsar A. Mantashyan ◽  
Hayk A. Sarkisyan ◽  
Eduard M. Kazaryan ◽  
Gabriel Bester ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Raman Scattering ◽  
Cross Section ◽  
Core Shell ◽  
Interband Absorption ◽  
Photoluminescence Spectra ◽  
Cds Quantum Dots ◽  
Mass Approximation ◽  
Numerical Discretization ◽  
Size Dispersion

By using the numerical discretization method within the effective-mass approximation, we have theoretically investigated the exciton-related Raman scattering, interband absorption and photoluminescence in colloidal CdSe/CdS core/shell quantum dots ensemble. The interband optical absorption and photoluminescence spectra have been revealed for CdSe/CdS quantum dots, taking into account the size dispersion of the ensemble. Numerical calculation of the differential cross section has been presented for the exciton-related Stokes–Raman scattering in CdSe/CdS quantum dots ensemble with different mean sizes.

On the mechanism of photocatalytic reactions on CuxO@TiO2 core-shell photocatalyst

2021 ◽  
Author(s):  
Kunlei Wang ◽  
Zuzanna Bielan ◽  
M. Ando ◽  
Marcin Janczarek ◽  
Dong Zhang ◽  
...  
Keyword(s):  
Charge Carriers ◽  
Environmental Applications ◽  
Core Shell ◽  
Highly Active ◽  
Photocatalytic Reactions

Titania (titanium(IV) oxide) is highly active, stable, cheap and abundant photocatalyst, and thus commonly applied in various environmental applications. However, two main shortcomings of titania, i.e., charge carriers’ recombination and...

Energy Levels of Core-Excited States and Atomic Oscillator Strengths for Boron and Boron-like Ions (abstract)

2009 ◽  
Author(s):  
Magda A. Rahim ◽  
Beverly Karplus Hartline ◽  
Renee K. Horton ◽  
Catherine M. Kaicher
Keyword(s):  
Excited States ◽  
Energy Levels ◽  
Oscillator Strengths
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