نتایج جستجو برای: van der waals

تعداد نتایج: 202706  

Journal: :The Journal of chemical physics 2015
Bing-Sui Lu Ali Naji Rudolf Podgornik

We analyze van der Waals interactions between two rigid polymers with sequence-specific, anisotropic polarizabilities along the polymer backbones, so that the dipole moments fluctuate parallel to the polymer backbones. Assuming that each polymer has a quenched-in polarizability sequence which reflects, for example, the polynucleotide sequence of a double-stranded DNA molecule, we study the van ...

Journal: :Physical chemistry chemical physics : PCCP 2011
Micael J T Oliveira Silvana Botti Miguel A L Marques

In this work we show how the ab initio determination of van der Waals coefficients within time-dependent density functional theory can be used to build efficient and accurate atomistic models that describe the long-range interactions of proteins with other proteins and of proteins with semi-conducting surfaces. The model parameters are fitted so that they reproduce the ab initio van der Waals c...

Journal: :Dalton transactions 2013
Santiago Alvarez

The distribution of distances from atoms of a particular element E to a probe atom X (oxygen in most cases), both bonded and intermolecular non-bonded contacts, has been analyzed. In general, the distribution is characterized by a maximum at short E···X distances corresponding to chemical bonds, followed by a range of unpopulated distances--the van der Waals gap--and a second maximum at longer ...

2004
DONG FU JIANZHONG WU

A self-consistent density-functional approach is presented for describing the phase behaviour and interfacial tensions of van der Waals fluids represented by the hard-core Yukawa (HCY), Lennard-Jones (LJ) and square-well (SW) potentials. The excess Helmholtz energy functional is formulated in terms of a modified fundamental measure theory (MFMT) for the shortranged repulsion and a density-gradi...

Journal: :Nature communications 2014
Jiaqi He Nardeep Kumar Matthew Z Bellus Hsin-Ying Chiu Dawei He Yongsheng Wang Hui Zhao

The newly discovered two-dimensional materials can be used to form atomically thin and sharp van der Waals heterostructures with nearly perfect interface qualities, which can transform the science and technology of semiconductor heterostructures. Owing to the weak van der Waals interlayer coupling, the electronic states of participating materials remain largely unchanged. Hence, emergent proper...

Journal: :Physical chemistry chemical physics : PCCP 2017
Antti J Karttunen Denis Usvyat Martin Schütz Lorenzo Maschio

van der Waals interactions are known to play a key role in the formation of weakly bound solids, such as molecular or layered crystals. Here we show that the correct quantum-chemical description of van der Waals dispersion is also essential for a correct description of the relative stability between purely covalently-bound solids like silicon allotropes. To this end, we apply periodic local MP2...

2004
SLAVA V. ROTKIN

The paper reviews quantum and classical effects which arise in physics of nanotube devices. Knowledge of nanotube electronic structure has been used for a calculation of quantum capacitance and quantum terms in van der Waals energy. Combining analytical theory and quantum mechanical micromodels I worked out a description for nanoelectromechanical devices, for example, electromechanical switch. ...

2016
Shigeki Kawai Adam S Foster Torbjörn Björkman Sylwia Nowakowska Jonas Björk Filippo Federici Canova Lutz H Gade Thomas A Jung Ernst Meyer

Van der Waals forces are among the weakest, yet most decisive interactions governing condensation and aggregation processes and the phase behaviour of atomic and molecular matter. Understanding the resulting structural motifs and patterns has become increasingly important in studies of the nanoscale regime. Here we measure the paradigmatic van der Waals interactions represented by the noble gas...

Journal: :Journal of colloid and interface science 1998
Zheng Gu

A modified two-dimensional van der Waals equation model was proposed for the prediction of multicomponent gas-solid adsorption isotherms from corresponding single-component adsorption equilibrium data. The model was used to predict adsorption isotherms of CO-CO2 mixtures and CO2-N2 mixtures on Cu(I)-NaY zeolite. Experimental adsorption equilibrium data of the two systems were compared with resu...

2008
Romesh C. Batra Maurizio Porfiri Davide Spinello

We study the influence of von Karman nonlinearity, van der Waals force, and a athermal stresses on pull-in instability and small vibrations of electrostatically actuated mi-croplates. We use the Galerkin method to develop a tractable reduced-order model for elec-trostatically actuated clamped rectangular microplates in the presence of van der Waals forcesand thermal stresses. More specifically,...

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