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Ancilotto, F., Barranco, M., Navarro, J., & Pi, M. (2016). A Density Functional Approach to Para-hydrogen at Zero Temperature. J. Low Temp. Phys., 185(1-2), 26–38.
Abstract: 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 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) clusters indicating that for small N values a liquid-like character of the clusters prevails, while solid-like clusters are instead energetically favored for .
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Ancilotto, F., Barranco, M., Navarro, J., & Pi, M. (2011). Cavitation of electron bubbles in liquid parahydrogen. Mol. Phys., 109(23-24), 2757–2762.
Abstract: 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 pH(2). 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.
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Navarro, J., Ancilotto, F., Barranco, M., & Pi, M. (2011). Toward a Density Functional Description of Liquid pH(2). J. Phys. Chem. A, 115(25), 6910–6917.
Abstract: A finite-temperature density functional approach to describe the properties of parahydrogen in the liquid vapor coexistence region is presented. The first proposed functional is zero-range, where the density-gradient term is adjusted so as to reproduce the surface tension of the liquid vapor interface at low temperature. The second functional is finite-range and, while it is fitted to reproduce bulk pH(2) properties only, it is shown to yield surface properties in good agreement with experiments. These functionals are used to study the surface thickness of the liquid vapor interface, the wetting transition of parahydrogen on a planar Rb model surface, and homogeneous cavitation in bulk liquid pH(2).
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Pi, M., Barranco, M., Navarro, J., & Ancilotto, F. (2012). Nucleation and cavitation in parahydrogen. Chem. Phys., 399, 213–217.
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.
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