نتایج جستجو برای: van der waals

تعداد نتایج: 202706  

Journal: :Physical review letters 2015
Felix Huttmann Antonio J Martínez-Galera Vasile Caciuc Nicolae Atodiresei Stefan Schumacher Sebastian Standop Ikutaro Hamada Tim O Wehling Stefan Blügel Thomas Michely

We use scanning tunneling microscopy to visualize and thermal desorption spectroscopy to quantitatively measure that the binding of naphthalene molecules to graphene, a case of pure van der Waals interaction, strengthens with n and weakens with p doping of graphene. Density-functional theory calculations that include the van der Waals interaction in a seamless, ab initio way accurately reproduc...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید بهشتی - دانشکده علوم 1389

چکیده ندارد.

Journal: :journal of physical & theoretical chemistry 2015
iffat r. arisa

the internal structure of a molecule can be presented in terms of intra-molecular (i.e., inter atomic)and inter-molecular energies such as van der waals, bond and bending, torsion, and inversion energy.in this study, changes in molecular energies of individual asphalt components are evaluated as afunction of physical aging factors. the factors for physical aging such as temperature and pressure...

Journal: :Chemistry Central Journal 2007
Alexei V Finkelstein

BACKGROUND The prediction of ligand binding or protein structure requires very accurate force field potentials - even small errors in force field potentials can make a 'wrong' structure (from the billions possible) more stable than the single, 'correct' one. However, despite huge efforts to optimize them, currently-used all-atom force fields are still not able, in a vast majority of cases, even...

Journal: :Nano letters 2014
Mehmet Aykol Bingya Hou Rohan Dhall Shun-Wen Chang William Branham Jing Qiu Stephen B Cronin

We investigate the role of weak clamping forces, typically assumed to be infinite, in carbon nanotube mechanical resonators. Due to these forces, we observe a hysteretic clamping and unclamping of the nanotube device that results in a discrete drop in the mechanical resonance frequency on the order of 5-20 MHz, when the temperature is cycled between 340 and 375 K. This instability in the resona...

2002
SLAVA V. ROTKIN

We have developed a model for the calculation of van der Waals force for layered systems with axial symmetry. Our result can be applied to compute the cohesion of a carbon nanotube to a substrate, the cohesion between nanotubes, and between shells of multiwall nanotubes. We have obtained unusal power laws for the distance dependence of the many-body van der Waals potential.

2013
Arvind Narayanaswamy Yi Zheng

We derive the van der Waals energy and pressure in a planar multilayer system with arbitrary number of dissipative films between two half-spaces. A unique feature of this work is that the entire analysis is performed on the real frequency axis instead of summation over Matsubara frequencies on the imaginary frequency axis. The expression we obtain for van der Waals energy is a generalization of...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2008
shipra baluja jagdish movaliya

the ultrasonic velocity, density and viscosity of some schiff bases of 4-amino benzoic acid  were measured in 1,4-dioxane and dimethylformamide at 308.15 k. various acoustical properties such as isentropic compressibility (ks), rao’s molar sound function (rm), the van der waals constant (b), molar compressibility (w), inter molecular free length (lf), relaxation strength (r), internal pressure ...

امیری, پیمان , صالحی, حمداله , معدلی , محمد ,

In this paper, the long-range Van Der Walls dispersion force correction (vdW-DF) for a combined system consisting of an Ag-chain adsorbed on a monolayer of graphene is studied. Calculations are based on density functional theory (DFT) performed by using various LDA, PBE and BLYP approximations. Since Ag chain is weakly adsorbed on graphene sheet, the Van Der Waals contribution to the total adso...

Journal: :The Journal of chemical physics 2004
R Podgornik V A Parsegian

Working at the Lifshitz level, we investigate the van der Waals interactions across a series of layers with a periodic motif. We derive the complete form of the van der Waals interaction as an explicit function of the number of periodic layers. We then compare our result with an approximation based on an anisotropic-continuum representation of the stratified medium. Satisfactory agreement betwe...

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