Many-body interactions among adsorbed atoms and molecules within carbon nanotubes and in free space

Abstract

Studies of three-dimensional and two-dimensional condensed phases have shown that manybody interactions contribute ∼ 10% to the equations of state of noble gases. This paper assesses the importance of three-body triple dipole interactions for quasi-one-dimensional phases of He, Ne, H2, Ar, Kr and Xe confined within interstitial channels or on the external surfaces of nanotube bundles. We find the substrate-mediated contribution to be substantial: for interstitial H2 the well depth of the effective pair potential is reduced to approximately one half of its value in free space.We carry out ab initio calculations on linear and equilateral triangular configurations of (H2)3 and find that overlap interactions do not greatly change the DDD interaction in the linear configuration when the lattice spacing is greater than about 3Å. However, the DDD interaction alone is clearly insufficient for the triangular configurations studied.

Outlook and challenges for hydrogen storage in nanoporous materials

“…This is more than just a geometric consideration because in adsorption a foreign body is also included (the solid) and therefore the third body, in three-body interactions, for example, may be a framework ion. Further details on the importance of this can be found in Kostov et al [115].…”

Isotopic effects of hydrogen adsorption in carbon nanotubes

“…Recently, Cole and co-workers 28,29 have estimated the effective correction in the two-body potential due to three-body interactions between two particles and the carbon atoms of the nanotube wall. This three-body interaction has been modeled by the well-known tripledipole interaction derived by Axilrod and Teller, 30 a potential energy contribution that is mostly repulsive.…”

Phonons and specific heat of neon and methane on the surface of a nanotube bundle

“…30,31 The adsorbate-adsorbate interaction is a LJ potential, characterized by the parameters gg and ⑀ gg ͑see Table I͒. Deviations may arise, in principle, due to three-body forces between the adatoms, such as Axilrod-Teller-Muto forces, 32,33 and substrate mediated forces, such as those of McLachlan, 34,35 which are not included in U LJ (r i j ). 36 We also neglect the interactions between adsorbates in neighboring grooves, because of the large distance between adjacent grooves.…”