Substrate-mediated dispersion interaction between adsorbed atoms and molecules

The van der Waals and Casimir-Polder interaction of different atoms with graphene is investigated using the Dirac model which assumes that the energy of quasiparticles is linear with respect to the momentum. The obtained results for the van der Waals coefficients of hydrogen atoms and molecules and atoms of metastable He * and Na as a function of separation are compared with respective results found using the hydrodynamic model of graphene. It is shown that, regardless of the value of the gap parameter, the Dirac model leads to much smaller values of the van der Waals coefficients than the hydrodynamic model. The experiment on quantum reflection of metastable He * and Na atoms on graphene is proposed which is capable to discriminate between the two models of the electronic structure of graphene. In this respect the parameters of the phenomenological potential for both these atoms interacting with graphene described by different models are determined.

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“…For a hydrogen atom it was found [40] that α(0) ≡ α a (0) = 4.50 a.u. and ω 0 ≡ ω 0a = 11.65 eV (remind that In Fig.…”

Section: Interaction Of Hydrogen Atoms and Molecules With Graphenementioning

confidence: 99%

Comparison of hydrodynamic and Dirac models of dispersion interaction between graphene and H,He∗, or Na atoms

et al. 2010

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“…and ω m = 14.09 eV, respectively [39]. Now let us consider the problem of dielectric permittivities of graphite ε x and ε z along the imaginary frequency axis.…”

Section: Dielectric Permittivities Of Graphite and Dynamic Polarimentioning

confidence: 99%

Van der Waals interaction between microparticle and uniaxial crystal with application to hydrogen atoms and multiwall carbon nanotubes

2005

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The Lifshitz theory of the van der Waals force is extended for the case of an atom (molecule) interacting with a plane surface of an uniaxial crystal or with a long solid cylinder or cylindrical shell made of isotropic material or uniaxial crystal. For a microparticle near a semispace or flat plate made of an uniaxial crystal the exact expressions for the free energy of the van der Waals and Casimir-Polder interaction are presented. An approximate expression for the free energy of microparticle-cylinder interaction is obtained which becomes precise for microparticle-cylinder separations much smaller than cylinder radius. The obtained expressions are used to investigate the van der Waals interaction between hydrogen atoms (molecules) and graphite plates or multiwall carbon nanotubes. To accomplish this the behavior of graphite dielectric permittivities along the imaginary frequency axis is found using the optical data for the complex refractive index of graphite for the ordinary and extraordinary rays. It is shown that the position of hydrogen atoms inside multiwall carbon nanotubes is energetically preferable compared with outside.

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“…where n H is the concentration of atoms (or molecules) and α H (iω) is the polarizability of atomic hydrogen (or molecular hydrogen or helium atoms) as given by Rauber et al [32].…”

Section: Theoretical Sectionmentioning

confidence: 99%

Repulsive van der Waals forces due to hydrogen exposure on bilayer graphene

Boström

Sernelius

2012

Phys. Rev. A

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We consider the effect of atomic hydrogen exposure to a system of two undoped sheets of graphene grown near a silica surface (the first adsorbed to the surface and the second freestanding near the surface). In the absence of atomic hydrogen, the van der Waals force between the sheets is attractive at all separations, causing the sheets to come closer together. However, with the addition of atomic hydrogen between the sheets, the long-range van der Waals interaction turns repulsive at a critical concentration. The underlying triple layer structure (SiO 2 -atomic hydrogen gas-air) gives rise to a long-range repulsion that at large-enough separations dominates over the more rapidly decaying attraction between the two-dimensional undoped graphene sheets (and between the outer graphene sheet and SiO 2 ). This may be an avenue to tune the separation between two graphene sheets with the gas concentration. The doping of the graphene layers increases the attractive part of the interaction and hence reduces the net repulsive interaction.

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Substrate-mediated dispersion interaction between adsorbed atoms and molecules

Cited by 168 publications

References 11 publications

Comparison of hydrodynamic and Dirac models of dispersion interaction between graphene and H,He∗, or Na atoms

Comparison of hydrodynamic and Dirac models of dispersion interaction between graphene and H,He∗, or Na atoms

Van der Waals interaction between microparticle and uniaxial crystal with application to hydrogen atoms and multiwall carbon nanotubes

Repulsive van der Waals forces due to hydrogen exposure on bilayer graphene

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