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The method, recently developed to include van der Waals interactions in the density functional theory by using the maximally localized Wannier functions, is extended to the case of atoms and fragments weakly bonded (physisorbed) to metal and semimetal surfaces, thus opening the way to realistic simulations of surface-physics processes, where van der Waals interactions play a key role. Successful applications to the case of Ar on graphite and of Ar, He, and H2 on the Al(100) surface are presented. [ABSTRACT FROM AUTHOR]

Electron bubbles in superfluid 4He have been recently observed in low-temperature cavitation measurements under experimental conditions where quantized vortices are also present in the liquid, and which might be attached to the bubbles. We have calculated, within density functional theory, the structure and energetics of electron bubbles pinned to linear vortices in liquid 4He at low temperature, and the pressure at which such structures become mechanically unstable. Our results are in semiquantitative agreement with the experiments. We discuss dynamical effects not included in the theoretical model used in the present calculations, and which could explain some discrepancies between our results and the experimental data. [ABSTRACT FROM AUTHOR]

We have developed a density functional (DF) built so as to reproduce either the metastable liquid or the solid equation of state of bulk para-hydrogen, as derived from quantum Monte Carlo zero temperature calculations. As an application, we have used it to study the structure and energetics of small para-hydrogen clusters made of up to $$N=40$$ molecules. We compare our results for liquid clusters with diffusion Monte Carlo (DMC) calculations and find a fair agreement between them. In particular, the transition found within DMC between hollow-core structures for small N values and center-filled structures at higher N values is reproduced. The present DF approach yields results for (pH $$_2$$ ) $$_N$$ clusters indicating that for small N values a liquid-like character of the clusters prevails, while solid-like clusters are instead energetically favored for $$N \ge 15$$ . [ABSTRACT FROM AUTHOR]

Within a finite-temperature density functional approach, we have investigated the structure of electron bubbles in liquid parahydrogen below the saturated vapour pressure, determining the critical pressure at which electron bubbles explode as a function of temperature. The electron–parahydrogen interaction has been modelled by a Hartree-type local potential fitted to the experimental value of the conduction band-edge for a delocalized electron in pH2. We have found that the pressure for bubble explosion is, in absolute value, about a factor of two smaller than that of the homogeneous cavitation pressure in the liquid. Comparison with the results obtained within the capillary model shows the limitations of this approximation, especially as temperature increases. [ABSTRACT FROM AUTHOR]

We have studied the wetting behavior of neon on the surface of solid CO[sub 2] by means of density functional calculations. Our results suggest that a wetting transition occurs at a temperature about 5 K below the bulk critical temperature, accompanied by the characteristic first-order prewetting transitions slightly away from coexistence. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Abstract: We have used a density functional approach to investigate thermal homogeneous nucleation and cavitation in parahydrogen. The effect of electrons as seeds of heterogeneous cavitation in liquid parahydrogen is also discussed within the capillary model. [Copyright &y& Elsevier]

The DFT/vdW-WF method, recently developed to include the Van der Waals interactions in Density Functional Theory (DFT) using the maximally localized Wannier functions, is applied to the study of the adsorption of rare-gas atoms (Ne, Ar, Kr, and Xe) on the Cu(lll) and Pb(lll) surfaces at three high-symmetry sites. We evaluate the equilibrium binding energies and distances and the induced work-function changes and dipole moments. We find that for Ne, Ar, and Kr on the Cu(lll) surface the different adsorption configurations are characterized by very similar binding energies while the favored adsorption site for Xe on Cu(l 11) is on top of a Cu atom, in agreement with previous theoretical calculations and experimental findings and in common with other close-packed metal surfaces. Instead, the favored site is always the hollow one on the Pb(lll) surface, which therefore represents an interesting system where the investigation of high-coordination sites is possible. Moreover, the Pb(lll) substrate is subject, upon rare-gas adsorption, to a significantly smaller change in the work function (and to a correspondingly smaller induced dipole moment) than Cu(l 11 ). The roles of the chosen reference DFT functional and of different van der Waals corrections as well as their dependence on different rare-gas adatoms are also discussed. [ABSTRACT FROM AUTHOR]