Low coverage adsorption in cylindrical pores

Phase Diagrams of 4He on Flat and Curved Environments

“…There, we displayed two sets of similar symbols. The upper ones correspond to simulation results obtained by using the isotopic form of the C-He potential [13], while the lower symbols display the energies per particle derived from the use of the anisotropic potential [14]. We observe that both sets of data are very similar.…”

“…In this way, one recovers the experimental ground state and describes accurately the full experimental phase diagram [4]. In previous work [1,2], we have built the potential surfaces using an isotropic Lennard-Jones potential with parameters used in studies of 4 He adsorbed inside narrow nanotubes [13]. In spite of the fact that the phase diagram seems correctly described by central interactions it has been claimed that the corrugation produced by this model is incomplete.…”

“…Instead, in more recent simulations an explicit account of the sum of all the carbon-helium interactions has been included [1,17,18], making the resulting phase diagrams agree with available experimental data on graphite. In the present work, we further analyze the influence of the C-He interaction in the phase diagram by comparing the results obtained with two different potential models: an isotropic Lennard-Jones potential, used extensively in previous studies [13], and the anisotropic interaction proposed by Carlos and Cole to obtain a better agreement with certain experimental measurements [14].…”

Quasi-one-dimensional4Heinside carbon nanotubes

“…However, contrary to the situation for dilute classical gases [14][15][16], there are no many body calculations of quantum fluids inside nanotubes yet. In this work, we address the question of the quasi-one dimensionality of 4 He absorbed in a tube by a direct comparison between the results of diffusion Monte Carlo (DMC) for strictly 1D 4 He and 4 He inside a nanotube of radius equal to 3.42 A, which corresponds to a (5,5) armchair tube in the standard nomenclature [2].…”

“…In the present calculation, we have used the HFD-B(HE) Aziz potential for the He-He pair interaction [19], and the potential given by Stan and Cole [15] in their study of Lennard-Jones fluids in tubes for the He-tube one. Basically, they consider the nanotubes as smooth cylinders by making a z-average of the corresponding sum of all the C-He interactions.…”