scholarly journals On the Dielectric “Constant” of Proteins: Smooth Dielectric Function for Macromolecular Modeling and Its Implementation in DelPhi

2013 ◽  
Vol 9 (4) ◽  
pp. 2126-2136 ◽  
Author(s):  
Lin Li ◽  
Chuan Li ◽  
Zhe Zhang ◽  
Emil Alexov
Keyword(s):  
Dielectric Constant ◽  
Dielectric Function ◽  
Macromolecular Modeling

Measurement of the dielectric function spectra of low dielectric constant using the spectroscopic ellipsometry

2003 ◽  
Author(s):  
Masahiro Horie ◽  
Kamil Postava ◽  
Tomuo Yamaguchi ◽  
Kumiko Akashika ◽  
Hideki Hayashi ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Function ◽  
Spectroscopic Ellipsometry ◽  
Low Dielectric Constant ◽  
Low Dielectric

scholarly journals Modeling the Bulk and Nanometric Dielectric Functions of Au and Ag

2021 ◽  
Author(s):  
Brahim Ait Hammou ◽  
Abdelhamid El Kaaouachi ◽  
Abdellatif El Oujdi ◽  
Adil Echchelh ◽  
Said Dlimi ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Function ◽  
Imaginary Part ◽  
Complex Number ◽  
Theoretical Models ◽  
Electronic Transitions ◽  
Experimental Measurements ◽  
Mathematical Functions ◽  
Lorentz Theory ◽  
Critical Model

In this work, we model the dielectric functions of gold (Au) and silver (Ag) which are typically used in photonics and plasmonics. The modeling has been performed on Au and Ag in bulk and in nanometric states. The dielectric function is presented as a complex number with a real part and an imaginary part. First, we will model the experimental measurements of the dielectric constant as a function of the pulsation ω by appropriate mathematical functions in an explicit way. In the second part we will highlight the contributions to the dielectric constant value due to intraband and interband electronic transitions. In the last part of this work we model the dielectric constant of these metals in the nanometric state using several complex theoretical models such as the Drude Lorentz theory, the Drude two-point critical model, and the Drude three-point critical model. We shall comment on which model fits the experimental dielectric function best over a range of pulsation.

Optical properties of pure and TM-doped single-walled ZnO nanotubes (8,0) (TM = V and Co) by first principles calculations

2016 ◽  
Vol 30 (01) ◽  
pp. 1550255 ◽  
Author(s):  
R. Taghavi Mendi ◽  
M. Majidiyan Sarmazdeh ◽  
A. Boochani ◽  
S. M. Elahi ◽  
S. Naderi
Keyword(s):  
Dielectric Constant ◽  
Optical Properties ◽  
Energy Range ◽  
Dielectric Function ◽  
Optical Conductivity ◽  
Optical Transitions ◽  
Optical Reflectivity ◽  
Zno Nanotubes ◽  
Low Energies ◽  
Co Doped

In this paper, some optical properties of pure and transition metal-doped (TM = Co and V) single-walled ZnO nanotubes (8,0) (SWZnONT(8,0)) such as, real and imaginary parts of the dielectric function, optical conductivity, refractive index and optical reflectivity, were investigated. The calculations have been performed within framework of the density functional theory (DFT) using the full potential linearized augmented plane wave (FP-LAPW) and the generalized gradient approximation (GGA). The results show that, optical properties of SWZnONT(8,0) are anisotropic, especially at low energies and this anisotropy at low energies increases with doping of V in SWZnONT(8,0) while the Co-doped SWZnONT(8,0) behaves like pure SWZnONT(8,0). Doping of ZnO nanotubes has a significant impact on the value of the dielectric constant, so that due to the presence of V atom, the dielectric constant is increased up to three times. Study of the imaginary part of the dielectric function and optical conductivity showed that the important energy range for absorption processes and optical transitions is low energy range to 15 eV. The optical transitions have been studied based on band structure and density of states. The results of the optical reflectivity showed that these nanotubes are transparent in a wide energy ranges which provide them for using in transparent coatings. In addition, due to the reported magnetic properties for V- and Co-doped ZnO nanotubes, these nanotubes are suitable for using in spintronics and magneto-optic devices.

An improved quantum biochemistry description of the glutamate–GluA2 receptor binding within an inhomogeneous dielectric function framework

2017 ◽  
Vol 41 (14) ◽  
pp. 6167-6179 ◽  
Author(s):  
A. C. V. Martins ◽  
P. de-Lima-Neto ◽  
E. W. S. Caetano ◽  
V. N. Freire
Keyword(s):  
Dielectric Constant ◽  
Dielectric Function ◽  
Receptor Binding ◽  
Electrostatic Interaction ◽  
Protein Residues ◽  
Inhomogeneous Dielectric

A new methodology to define the inhomogeneous dielectric constant of protein residues, to apply to the calculation of protein–ligand properties such as the electrostatic interaction.

Studies of the Dielectric Constant of Thin Film Bismuth Nanowire Samples Using Optical Reectometry

2001 ◽  
Vol 635 ◽  
Author(s):  
M. R. Blacka ◽  
Y.-M. Lin ◽  
S. B. Cronin ◽  
O. Rabin ◽  
M. P adi ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Energy Range ◽  
Dielectric Function ◽  
Composite System ◽  
Incident Light ◽  
Light Polarization ◽  
Alumina Template ◽  
Medium Theory ◽  
Bismuth Nanowires ◽  
Amorphous Alumina

AbstractArrays of 10 to 120 nm diameter single crystalline bismuth nanowires havebeen formed inside amorphous alumina templates. ince bismuth has a small e ective mass compared to other materials, signi cant quantum mechanical con nement is expected to occur in wires with diameter less than 50nm. he subbands formed b yquantum con nement cause in teresting modi cations to the dielectric function of bismuth. his study measures the dielectric function of bismuth nanowires in an energy range where the e ects of quantum con nement are predicted (0.05 to 0.5e). Using F ourier transforminfrared re ectometry, the dielectric constant as a function of energy is obtained for the alumina/bismuth composite system. E ective medium theory is used to subtract the e ect of the alumina template from the measurement of the composite material, thus yielding the dielectric function of bismuth nanowires. A strong absorption peak is observed at ∼1000cm−1 in the frequency dependent dielectric function in the photon energy range measured. he dependence of the frequency and intensity of this oscillator on incident light polarization and wire diameter are reviewed. n addition, the dependence of the optical absorption on antimony and tellurium doping of the nanowires are reported.

Dielectric dispersion of salt‐water—saturated porous glass containing thin glass plates

Geophysics ◽  
1996 ◽  
Vol 61 (3) ◽  
pp. 722-734 ◽  
Author(s):  
Espen Haslund
Keyword(s):  
Dielectric Constant ◽  
Dielectric Function ◽  
Quantitative Difference ◽  
Experimental Result ◽  
Frequency Range ◽  
Formation Factor ◽  
Thin Glass ◽  
The Real ◽  
Frequency Level ◽  
Glass Plates

Complex permittivity (i.e., dielectric constant and conductivity) measurements are performed on porous, fused glass bead specimens, and the effect of the presence of glass plates is investigated systematically. Two types of plates are used in this investigation, relatively thick ones made from crushed cover slides and very thin ones made from crushed blown glass bubbles. As a reference, the response of specimens without plates is also measured. After saturating the specimens with conducting water, the effective dielectric function is measured over the frequency range of Maxwell‐Wagner dispersion. The dispersion strength increased with the addition of plates, an effect that is stronger for thinner plates. The dispersion frequency range is larger for thinner plates, but is independent of plate concentration for constant plate thickness. The experimental results are compared with the effective medium theory for the dielectric function of porous media containing plates due to Mendelson and Cohen and to Sen—an extension of the Sen Scala Cohen theory. The theoretical curves are fitted to the experimental points of the real dielectric constant by adjusting the depolarization parameter given by the aspect ratio of the plates. The effect of the plates on the dispersion predicted by the theory is found to be in good agreement with experimental result. The high‐frequency level of the real dielectric constant is almost unaffected by the plates as given by the theory. The low‐frequency level of the conductivity, or the formation factor, is found to vary with plate content, as also predicted by the theory. However, the quantitative difference between the theoretical and the experimental formation factor is generally found to be somewhat larger than the estimated experimental uncertainty. The theory is also fitted to data from the literature on a real rock specimen, and a close fit is obtained, together with encouraging estimates of porosity and formation factor.

SUBMILLIMETER CONDUCTIVITY AND DIELECTRIC CONSTANT OF La1.8Sr0.2CuO4 CERAMIC

1987 ◽  
Vol 01 (03n04) ◽  
pp. 867-870 ◽  
Author(s):  
B.P. Gorshunov ◽  
Yu. G. Goncharov ◽  
G.V. Kozlov ◽  
A.M. Prokhorov ◽  
A.S. Prokhorov ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Temperature Dependence ◽  
Dielectric Function ◽  
Energy Gap ◽  
Temperature Behavior ◽  
Backward Wave Oscillator ◽  
Temperature Range ◽  
Wave Oscillator ◽  
Temperature Dependence Of Conductivity ◽  
Superconducting Energy Gap

The temperature dependence of conductivity and dielectric function of the superconducting La1.8Sr0.2CuO4 ceramic is measured using backward-wave oscillator technique at the frequency 15 cm −1 and in the temperature range 5–300K. The temperature behavior of the parameters is found to be close to the classical one at frequencies lower than superconducting energy gap.

Formulation of Dielectric Behaviour of Composite Material

2013 ◽  
Vol 665 ◽  
pp. 168-171
Author(s):  
Ananya Banerjee ◽  
Aditi Sarkar ◽  
A. Sarkar
Keyword(s):  
Dielectric Constant ◽  
Composite Material ◽  
Magnetic Susceptibility ◽  
Dielectric Function ◽  
Simple Formula ◽  
Dielectric Behavior ◽  
Experimental Result ◽  
Effective Dielectric Constant ◽  
Magnetic Element ◽  
Theoretical Formulation

A simple formula for effective dielectric constant of composite material or DMD is proposed. In case of magnetic element in the composite the effect of magnetic susceptibility is taken into account to describe the dielectric behavior. A theoretical formulation of the proposed dielectric function along with an experimental result is presented here. The overall results are found to be good and consistent .

scholarly journals On the modeling of polar component of solvation energy using smooth Gaussian-based dielectric function

2014 ◽  
Vol 13 (03) ◽  
pp. 1440002 ◽  
Author(s):  
Lin Li ◽  
Chuan Li ◽  
Emil Alexov
Keyword(s):  
Dielectric Constant ◽  
Dielectric Function ◽  
Solvation Energy ◽  
Bulk Water ◽  
Dielectric Medium ◽  
Water Phase ◽  
Polar Component ◽  
Implicit Methods ◽  
Inhomogeneous Dielectric ◽  
Polar Solvation

Traditional implicit methods for modeling electrostatics in biomolecules use a two-dielectric approach: a biomolecule is assigned low dielectric constant while the water phase is considered as a high dielectric constant medium. However, such an approach treats the biomolecule–water interface as a sharp dielectric border between two homogeneous dielectric media and does not account for inhomogeneous dielectric properties of the macromolecule as well. Recently we reported a new development, a smooth Gaussian-based dielectric function which treats the entire system, the solute and the water phase, as inhomogeneous dielectric medium (Li L, Li C, Zhang Z, Alexor E, On the dielectric constant of proteins: Smooth dielectric function for macromolecular modeling and its implementation in Delphi, J Chem Theory Comput9(4):2126–2136, 2013). Here we examine various aspects of the modeling of polar solvation energy in such inhomogeneous systems in terms of the solute–water boundary and the inhomogeneity of the solute in the absence of water surrounding. The smooth Gaussian-based dielectric function is implemented in the DelPhi finite-difference program, and therefore the sensitivity of the results with respect to the grid parameters is investigated, and it is shown that the calculated polar solvation energy is almost grid independent. Furthermore, the results are compared with the standard two-media model and it is demonstrated that on average, the standard method overestimates the magnitude of the polar solvation energy by a factor 2.5. Lastly, the possibility of the solute to have local dielectric constant larger than of a bulk water is investigated in a benchmarking test against experimentally determined set of pKa's and it is speculated that side chain rearrangements could result in local dielectric constant larger than 80.

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