Some properties of solid helium and helium nanoclusters using the effective HFD-like interaction potential: Adsorption and desorption inside carbon nanotube

• Published in: Physica A Vol. 491; pp. 219 - 232
• Main Authors: Abbaspour, M., Akbarzadeh, H., Banihashemi, S.Z., Sotoudeh, A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2018
• Subjects: Adsorption; Carbon nanotube; Desorption; Helium nanocluster; Solid helium; Carbon nanotube; Solid helium; Desorption; Adsorption; Helium nanocluster
• ISSN: 0378-4371; 1873-2119
• DOI: 10.1016/j.physa.2017.09.017

We have calculated the zero equation of state of solid helium using a two-body Hartree–Fock dispersion (HFD)-like potential from molecular dynamics (MD) simulation. To take many-body forces into account, our simple and accurate empirical expression is used with the HFD-like potential without requiring an expensive three-body calculation. This potential model also includes the quantum effects for helium at low temperatures. The results indicate that our effective HFD-like potential improves the prediction of the classical two-body results to get better agreement with experiment than many other two-body and three-body potentials of helium reported in the literature. We have also simulated the adsorption and desorption processes of the (He)55, (He)147, (He)309, (He)561, and (He)923 icosahedral nanoclusters confined into the different armchair and zigzag CNTs from 0 to 50 K using our effective model. We have observed an interesting phenomenon at 0 K for helium. The nanoclusters adsorb to the inner CNT wall as a melting process. But, the heavier noble gas clusters (such as Ne and Xe) show the different behavior than the He clusters. They form a multilayered solid structure into the CNT at zero temperature and adsorb into the inner wall of the CNT at higher temperatures. Our results for He clusters show that the absolute value of the adsorption energy increases as the size of the nanocluster increases. The desorption process begins at a certain temperature and represents itself by a jump in the configurational energy values. We have also investigated the structural and dynamical properties of the confined helium nanoclusters during the adsorption and desorption processes at different temperatures. •An accurate effective model was used for solid helium and helium nanoclusters.•A new EoS of solid helium at zero kelvin was obtained using MD simulation.•Adsorption and desorption of noble gas nanoclusters into CNTs were simulated.•An interesting melting-like adsorption observed at 0 K for He clusters.•Structural and dynamical properties of the nanoclusters were also investigated.