Using a diffusion Monte Carlo technique, we calculated the phase diagram of 3He adsorbed on a first solid layer of a molecular hydrogen isotope (H2, HD, and D2) on top of graphite. The results are qualitatively similar in all cases: a two-dimensional gas spanning from the infinite dilution limit to a second-layer helium density of 0.048 ± 0.004 Å-2. That gas is in equilibrium with a 7/12 commensurate structure, more stable than any incommensurate triangular solid of similar density. These findings are in reasonably good agreement with available experimental data.
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http://dx.doi.org/10.1063/5.0218136 | DOI Listing |
J Chem Phys
August 2024
Departament de Física, Universitat Politècnica de Catalunya, Campus Nord B4-B5, 08034 Barcelona, Spain.
Using a diffusion Monte Carlo technique, we calculated the phase diagram of 3He adsorbed on a first solid layer of a molecular hydrogen isotope (H2, HD, and D2) on top of graphite. The results are qualitatively similar in all cases: a two-dimensional gas spanning from the infinite dilution limit to a second-layer helium density of 0.048 ± 0.
View Article and Find Full Text PDFJ Magn Reson
May 2024
Kazan Federal University, Institute of Physics, Kremlevskaya 18, Kazan 420008, Russian Federation.
The spin kinetics of adsorbed and liquid He in contact with a mixture of LaF (99.67 %) and DyF (0.33 %) 20 nm powders at temperatures of 1.
View Article and Find Full Text PDFFront Chem
October 2023
Center for Interstellar Catalysis, Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark.
The dynamics of water diffusion on carbon surfaces are of interest in fields as diverse as furthering the use of graphene as an industrial-coating technology and understanding the catalytic role of carbon-based dust grains in the interstellar medium. The early stages of water-ice growth and the mobility of water adsorbates are inherently dependent on the microscopic mechanisms that facilitate water diffusion. Here, we use He spin-echo quasi-inelastic scattering to probe the microscopic mechanisms responsible for the diffusion of isolated water molecules on graphene-covered and bare Ir(111).
View Article and Find Full Text PDFNat Commun
October 2022
Low Temperature Laboratory, Department of Applied Physics, Aalto University School of Science, P.O. Box 15100, FI-00076, Espoo, Finland.
Low dimensional fermionic quantum systems are exceptionally interesting because they reveal distinctive physical phenomena, including among others, topologically protected excitations, edge states, frustration, and fractionalization. Our aim was to confine He on a suspended carbon nanotube to form 2-dimensional Fermi-system. Here we report our measurements of the mechanical resonance of the nanotube with adsorbed sub-monolayer down to 10 mK.
View Article and Find Full Text PDFPhys Chem Chem Phys
April 2021
Cavendish Laboratory, University of Cambridge, Cambridge CB30HE, UK.
The adsorption of sodium on Ru(0001) is studied using He spin-echo spectroscopy (HeSE), molecular dynamics simulations (MD) and density functional theory (DFT). In the multi-layer regime, an analysis of helium reflectivity, gives an electron-phonon coupling constant of λ = 0.64 ± 0.
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