نتایج جستجو برای: van der waals

تعداد نتایج: 202706  

Among the intermolecular interactions, the Casimir and van der Waals forces are the most important forces that highly affect the behavior of nanostructures. This paper studies the effect of such forces on the adhesion of cantilever freestanding nanostructures. The nanostructures are made of a freestanding nano-beam which is suspended between two upper and lower conductive surfaces. The linear s...

سمیعی, الهام, صفری, حسن,

In this study, thermal Casimir-Polder potential is calculated for an atom in the presence of a dielectric sphere using the formula given in terms of the Green’s function. Then, the limiting cases of large and small sphere are investigated. In the limiting case of a large sphere, the formula of thermal potential for an excited atom in the presence of a dielectric half-space and then a perfectly ...

Journal: :Nano letters 2016
Deep Jariwala Artur R Davoyan Giulia Tagliabue Michelle C Sherrott Joeson Wong Harry A Atwater

We demonstrate near-unity, broadband absorbing optoelectronic devices using sub-15 nm thick transition metal dichalcogenides (TMDCs) of molybdenum and tungsten as van der Waals semiconductor active layers. Specifically, we report that near-unity light absorption is possible in extremely thin (<15 nm) van der Waals semiconductor structures by coupling to strongly damped optical modes of semicond...

2002
Gil Katz Yehuda Zeiri Ronnie Kosloff

A time-dependent three-dimensional nonadiabatic computation study of the photodissociation of the van der Waals Na FH molecule was performed for total J 1⁄4 0. A very low probability of photo-reaction to produce NaF+H was observed from most initial conditions. Enhancement of the NaF+H product was observed for the isotopically substituted Na FD. The three-dimensional calculations are in qualitat...

2017
Theodoros Tsatsoulis Felix Hummel Denis Usvyat Martin Schütz George H Booth Simon S Binnie Michael J Gillan Dario Alfè Angelos Michaelides Andreas Grüneis

We present a comprehensive benchmark study of the adsorption energy of a single water molecule on the (001) LiH surface using periodic coupled cluster and quantum Monte Carlo theories. We benchmark and compare different implementations of quantum chemical wave function based theories in order to verify the reliability of the predicted adsorption energies and the employed approximations. Further...

2007

• Remarks and observations: (1) The tail of the van der Waals attractive potential (∝ r) extends to very long sep­ arations. Yet, its integral in eq.(V.39) is dominated by contributions from the short scales r0. In this limited context, the van der Waals potential is short-ranged, and results in corrections to the ideal gas behavior that are analytical in density n, leading to the virial series...

Journal: :Physical review letters 2017
Nancy Quiros Naima Tariq Timur V Tscherbul Jacek Kłos Jonathan D Weinstein

We have used laser ablation and helium buffer-gas cooling to produce titanium-helium van der Waals molecules at cryogenic temperatures. The molecules were detected through laser-induced fluorescence spectroscopy. Ground-state Ti(a^{3}F_{2})-He binding energies were determined for the ground and first rotationally excited states from studying equilibrium thermodynamic properties, and found to ag...

Journal: :The Journal of chemical physics 2010
Satoru G Itoh Hisashi Okumura Yuko Okamoto

We present a new type of the Hamiltonian replica-exchange method, where the van der Waals radius parameter and not the temperature is exchanged. By decreasing the van der Waals radii, which control spatial sizes of atoms, this Hamiltonian replica-exchange method overcomes the steric restrictions and energy barriers. Furthermore, the simulation based on this method escapes from the local-minimum...

1997
Stanley J. Brodsky Gerald A. Miller

The gluon-exchange contribution to J/ψ-nucleon scattering is shown to yield a sizeable scattering length of about -0.25 fm, which is consistent with the sparse available data. Hadronic corrections to gluon exchange which are generated by ρπ and DD intermediate states of the J/ψ are shown to be negligible. We also propose a new method to study J/ψ-nucleon elastic scattering in the reaction π+d→ ...

2013
Florin Bobaru F Bobaru

The peridynamic method is used here to analyse the effect of van der Waals forces on the mechanical behaviour and strength and toughness properties of three-dimensional nanofibre networks under imposed stretch deformation. The peridynamic formulation allows for a natural inclusion of long-range forces (such as van der Waals forces) by considering all interactions as ‘long-range’. We use van der...

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