نتایج جستجو برای: dielectric function

تعداد نتایج: 1248395  

Journal: :Physical chemistry chemical physics : PCCP 2016
M Grüning C Attaccalite

We calculated the frequency dependent macroscopic dielectric function and second-harmonic generation of cubic ZnS, ZnSe and ZnTe within time-dependent density-polarisation functional theory. The macroscopic dielectric function is calculated in a linear response framework, and second-harmonic generation in a real-time framework. The macroscopic exchange-correlation electric field that enters the...

Journal: :The Journal of chemical physics 2012
Stephan Gekle Roland R Netz

Proteins, molecules, and macromolecular assemblies in water are surrounded by a nanometer-sized hydration layer with properties very different from bulk water. Here, we use classical molecular dynamics simulations to study the dielectric response of hydration water next to hydrophobic and hydrophilic planar surfaces. We find the interfacial dielectric absorption of water to be strongly anisotro...

Recently, photonic crystals doped with liquid crystal (LC) material havegained much research interest. In this article new ternary one-dimensional photoniccrystal introduced and studied. The liquid crystal layer of 5CB and 5PCH is sandwichedby two dielectric layers. For the first time, we use four structures SiO2/UCF35/CaF2,SiO2/5CB/CaF2, NFK51/UCF35/NPSK53 and NFK51/5CB/NPSK53. The effect ofte...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2004
T Ambjörnsson S P Apell G Mukhopadhyay

We derive an expression for the polarizability of an ellipsoidally shaped cell-like structure at field frequencies where membrane molecular resonances (vibrational and electronic) are important. We first present analytical results for the dielectric function of a flat, dipole coupled, bilayer consisting of molecules with one prominent resonance frequency. Due to the nature of the dipole couplin...

2004
B. N. Das S. B. Chakrabarty K. Siva Rama Rao

The paper presents a method for the evaluation of variation of capacitance of a dielectric coated two-wire line of parallel cylinders, each of unit radius with a change in thickness of the dielectric along the radial direction. A conformal transformation is used to transform the conductor and dielectric boundaries to appropriate contours extending over a fixed region along the imaginary axis in...

Journal: :International Journal of Molecular Sciences 2009
Guo-Zhu Jia Ka-Ma Huang Li-Jun Yang Xiao-Qing Yang

In this paper, we study the dielectric properties of water-N,N dimethylformamide (DMF) mixtures over the whole composition range using a molecular dynamics (MD) simulation. The static and microwave frequency-dependent dielectric properties of the mixtures are calculated from MD trajectories of at least 2 ns length and compared to those of available measurements. We find that the short-ranged st...

2010
Hua Bao Xiulin Ruan

Spectral reflectance of GaAs from infrared (IR) to ultra-violet (UV) bands is predicted using ab initio calculations. We first predict the spectral dielectric function. Two major mechanisms exist for different photon wavelength, namely, photon–electron coupling in the UV to near-IR region and photon–phonon coupling in the far-IR region. For the near-IR to UV band, the electronic band structure ...

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In the present work, the effect of sintering parameters including sintering temperature, soaking time, and heating rate on densification, microstructure, and dielectrical properties of bismuth titanate (Bi4Ti3O12) ceramics were investigated. Bismuth titanate was synthesized by the solid state method and titanium oxide and bismuth oxide used as raw materials. X-ray diffraction (XRD) indicated, p...

2011
Mahmoud Soltani Reza Alimardani

Almost all properties of grains and seeds depend on moisture content. One of these properties is dielectric constant. Therefore capacitive sensor is used in precision agriculture widely. In this paper, a cylindrical capacitor was used to measure dielectric constant of seed. By measuring the dielectric constant, the moisture content of grains may be predicted. Change in dielectric constant of co...

1999
Yiannis N. Kaznessis Davide A. Hill Edward J. Maginn

We consider the dielectric strength and dielectric relaxation of dilute and semidilute solutions of polymers in a Θ solvent. A molecular dynamics technique is employed and the simulation results are contrasted with dielectric spectroscopy measurements, providing an insight into the molecular factors that affect the experimental behavior. The relation between the dielectric strength and the end-...

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