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Distributed polarizability of fullerene [2+1]-adducts C60X (n?=?1 and 2) with symmetric addends?X??=?CH2 and O: A fresh view on the effect of positional isomerism
摘要： We have performed a site-specific analysis of the mean polarizability of fullerene [2+1]-adducts C60Xn (n = 1 and 2) with symmetric addends X = CH2 and O using the distributed polarizability model. We have found that the contributions from the fullerene core and addends to the molecular polarizability are not the same for different regioisomeric C60X2: the core contribution linearly decreases and the addend contribution linearly increases with the distance between the addends (or the functionalized bonds of the C60 cage). Additionally, the contributions are sensible to the degree of the fullerene core functionalization: the contribution of the C60 core decreases with the number of the attached addends due to reducing its π-electronic system.
关键词： isomerism,additive polarizability,polarizability,distributed polarizability,fullerene,fullerene adducts
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Budapest (2018.7.1-2018.7.5)] 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Method for Calculating Electronic Polarizability of Water Molecules and Refractive Index
摘要： A method for calculating the electronic polarizability of water molecules is proposed. In the approximation of this method, the electronic components of the hyperpolarizability of the first and second order for the water molecule are determined.
关键词： water molecule,electron polarizability,refractive index,hyperpolarizability,electronic polarizability,molar refraction
更新于2025-09-23 15:22:29
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Nonresonant Polarized Raman Spectra Calculations of Nitrogen-Doped Single-Walled Carbon Nanotubes: Diameter, Chirality, and Doping Concentration Effects
摘要： Raman spectra of nitrogen-doped single-walled carbon nanotubes are calculated using the spectral moment’s method combined with the bond polarizability model. The influence of the nanotube diameter and chirality is investigated. We also address the important question of the effect of the N-doping concentration, and we propose an equation to estimate the doping concentration from the knowledge of the tube diameter and the frequency of the radial breathing mode.
关键词： spectral moment’s method,Raman spectra,N-doping concentration,nanotube diameter,nitrogen-doped single-walled carbon nanotubes,bond polarizability model,chirality
更新于2025-09-23 15:21:01
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Polarizability of Radially Inhomogeneous Subwavelength Spheres
摘要： In this work the polarizability of a subwavelength core-shell sphere is considered, where the shell exhibits a radially inhomogeneous permittivity profile. The mathematical treatment of the electrostatic polarizability is formulated in terms of the scattering potentials and the corresponding scattering amplitudes. As a result, a generalized expression of the polarizability is presented to be dependent of the radial inhomogeneity function. The extracted general model is applied for two particular cases, i.e., a power-law profile and a new class of permittivity profiles that exhibit exponential radial dependence. The proposed analysis quantifies in a simple manner the inhomogeneity effects, allowing the direct implementation of naturally or artificially occurring permittivity inhomogeneities for a wide range of applications within and beyond the metamaterial paradigm. Specifically, a special case of symmetric-antisymmetric resonant plasmonic degeneracy is identified and shown for the case of a core-shell sphere with a power-law permittivity profile. This degeneracy could be used for the experimental identification of inhomogeneity-induced effects or for applications where a strong coupling resonant regime is required. Furthermore, the described analysis opens avenues towards the phenomenological and first-principles modeling of the electrodynamic scattering effects for graded-index plasmonic particles at the nanoscale. Finally, such a description can be readily used either for the benchmarking of novel computational methods incorporating inhomogeneous materials or for inverse scattering purposes.
关键词： inverse scattering,subwavelength,core-shell sphere,scattering potentials,metamaterial,exponential radial dependence,polarizability,scattering amplitudes,plasmonic degeneracy,radially inhomogeneous permittivity,power-law profile
更新于2025-09-23 15:21:01
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Giant Stark effect in coupled quantum wells: Analytical model
摘要： Coupled quantum wells have been proposed as candidates for highly polarizable structures due to their near-degenerate and dipole-coupled electronic states. Hence, many interesting applications in linear and nonlinear optics can be envisioned. We analyze this proposal considering a simple structure with a delta-function barrier separating the wells. While very substantial Stark shifts are certainly predicted for this geometry, perturbative estimates based on polarizabilities (and hyperpolarizabilities) fail beyond a critical ?eld strength that depends inversely on the barrier. Hence, a giant Stark effect due to near-degenerate states is invariably limited by a small critical ?eld. Our analytical (hyper) polarizability expressions are applied to ?nd quantitative Stark shifts for GaAs quantum wells and transition-metal dichalcogenide bilayers. The predicted Stark shifts and critical ?elds agree with the ?eld dependence observed in a range of available experiments.
关键词： Stark effect,hyperpolarizability,GaAs,transition-metal dichalcogenide bilayers,polarizability,coupled quantum wells
更新于2025-09-23 15:19:57
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Experimental and theoretical investigations of 4-hydroxy L-proline cadmium chloride nonlinear optical crystal
摘要： The solution grown structure 4-hydroxy L-proline cadmium chloride (4HLPCC) single crystal has been done by means of X-ray diffraction method. The computational quantum mechanical modelling method was performed with B3LYP level and LanL2DZ basis set to determine optimized geometry, dipolar moment, linear polarizability, first order hyperpolarizability, atomic charges of various atoms, thermodynamic parameters, HOMO-LUMO energy gap and vibrational frequencies of 4HLPCC. The vibrational frequencies of 4HLPCC were observed experimentally through FTIR and FT-RAMAN analyses and compared with theoretical frequencies. The electric properties were detected by dielectric studies. The frequency doubling of the grown crystal was made with Kurtz-Perry powder technique.
关键词： Polarizability,4-hydroxy L-proline cadmium chloride,DFT,Nonlinear optical properties,Hyperpolarizability
更新于2025-09-23 15:19:57
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Comparative studies on polarisability, and optical properties of BiZnBo–SLS and PbZnBo–SLS glass
摘要： Soda Lime Silica (SLS), mainly composed of SiO2, was utilised in this study as the source of SiO2 for fabrication of glass. A study of physical and optical properties was performed for the glass system of x [RmOn] (0.50?x) [ZnO] 0.20 [B2O3] 0.30 [SLS], where RmOn are Bi2O3 and PbO with x = 0.05, 0.10, 0.20, 0.30, 0.40, and 0.45 mol. The glass was prepared by melt-quenching method. Optical properties of the glass samples were obtained using UV–visible absorption measurements. The main objective of this study was to compare the structural, polarizability, and optical properties of these two series synthesized silica based glass. The structure of the glass system was determined by X-ray diffraction (XRD). The density and molar volume were found to increase as Bi2O3 and PbO concentration increased. The optical band gap, Eopt values for bismuth glasses were between 2.58 and 2.92 eV and varied from 2.42 to 2.92 eV for lead glasses. The highest concentration of Bi2O3 and PbO in glass system showed the smallest Eopt. Bi2O3 glass exhibit the significant value towards direct or indirect band gap in optoelectronic field compared to PbO glass. Refractive index of glass samples was measured by UV–visible spectrophotometer. The value lay between 2.42 and 2.52 for bismuth glass and 2.42 and 2.57 for lead glass and the value increased as bismuth ion (Bi3+) and lead ion (Pb2+) concentration increased. Metallisation criterion was investigated on the basis of refractive index and band gap. The metallisation criterion of the glass sample linearly decreased with increasing concentration of bismuth and lead ions as a result of increasing number of refractive indices and decreasing number of band gap energy. The positive value of metallisation criterion indicates that the glass materials are insulators or not metallic. In conclusion, the obtained results show that the addition of bismuth oxide in silica glass improved its structural and optical properties compared to lead glass.
关键词： UV–visible,Polarizability,Refractive index,Metallisation criterion,Energy band gap
更新于2025-09-19 17:15:36
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Effect of nanoparticle size to improvement in absorption in Plasmonic solar cell
摘要： In last decades, plasmonics gives very high attention and closely involves in the main domains of nanophotonics which can control of optical fields at the nanodimension level. Its most striking property is to concentrate and enhance the electromagnetic field on the nanometer scale especially in solar cell. In plasmonic field, Nobel metals used as nanoparticle where density of electron gas which oscillates at surface plasmon frequency at the same time also improves absorption by scattering. So the use of plasmonic in solar cell gives better opportunity to enhance efficiency by absorption as the optical spectrum loss are most part of total loss in solar cell. In this paper, we investigate the effect of nanoparticle dimension for enhancement of extinction in terms of absorption and scattering by means of surface plasmon and also studied finite-difference time domain based proposed model which shows improvement in various simulated surface plasmonic fields components.
关键词： extinction,absorption,polarizability,plasmonics,finite difference time domain,scattering,surface Plasmon polariton
更新于2025-09-16 10:30:52
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Polarizability of germanium quantum dots with spatially separated electrons and holes in Ge/Si heterostructures
摘要： In the framework of dipole approximation, it is shown that the quantities (the oscillator strengths of transitions, the dipole moments for transitions, and the polarizability) describing optical absorption on surface exciton states with spatially separated electrons and holes (the hole moves in the germanium quantum dot and the electron is localised over the spherical interface of the silicon quantum dot matrix) assume giant values considerably exceeding the typical values of the corresponding quantities for semiconductors under the action of low-intensity light.
关键词： transition dipole moments,polarizability,oscillator strength,Spatially indirect excitons,quantum dots,polarization interaction,Coulomb interaction
更新于2025-09-16 10:30:52
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Polarizability and Catalytic Activity Determine Good Titanium Oxide Crystals but Not Homogeneity in Solar Cells Using Photocatalysts on Both Electrodes
摘要： TiO2 is advantageous when used on the anode of a solar cell (SC) and achieves an electromotive force of 2 V when using another photocatalyst on the cathode (dual-photoelectrode fuel cell). However, both sufficient photocatalytic activity and electronic conductivity are required for the film, and these two requirements compete with each other. Herein, uniformly sized and shaped spheroidal, cubic, and “rhombic” TiO2 nanoparticles were synthesized, forming films using casting, slide, ball milling–slide (BS), and ball milling–mechanical (BD) methods. The AC/DC impedances of the films followed the order “rhombic”-ball milling–slide > “rhombic”-slide > cubic-slide > spheroidal-ball milling–mechanical > P25-casting ~ P25-slide ~ spheroidal-BS ~ spheroidal-slide ~ P25-ball milling–mechanical, demonstrating that “rhombic” and cubic TiO2 films were unsuitable for use on the SC photoanode. The reverse reaction rates of cathode reaction (water photo-oxidation), i.e., the 18O2 exchange reaction, were evaluated, which followed the order Cubic-TiO2 > Spher-TiO2 > Rhomb-TiO2 ~ P25-TiO2, demonstrating that the synthesized TiO2 was unsuitable for water oxidation. Polarizability and catalytic activity of TiO2 crystals were critical to maximize SC performance, and fluorescence peak intensity at 372–366 nm was well correlated to SC performance. P25-Slide on a photoanode at pH 1.78 and BiOCl-Cast on a photocathode at pH 2.00 enabled a maximum power of 85.2 μW cm?2 and an open-circuit voltage of 1.94 V.
关键词： Water oxidation,Impedance,Solar cell,Dual-photoelectrode fuel cell,TiO2,Photocatalyst,Polarizability,Isotope tracing
更新于2025-09-12 10:27:22