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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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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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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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Mateo, D., Pi, M., Navarro, J., & Toennies, J. P. (2013). A density functional study of the structure of small OCS@He-3(N) clusters. J. Chem. Phys., 138(4), 044321–8pp.
Abstract: Kohn-Sham density functional calculations are reported for the structures of clusters consisting of a carbonyl sulfide (OCS) molecule with N = 1, 8, 18, and 40 attached He-3 atoms. The N = 1 cluster ground state is highly localized at the molecular waist (donut ring position), but for higher levels of excitation becomes increasingly delocalized. The first magic cluster with 8 atoms has a significant density at both ends of the molecule in addition to the donut ring. With N = 18 He-3 atoms the molecule is enclosed by a magic number closed shell. Another magic stable structure consisting of two nearly isotropically spherical closed shells is found at N = 40. A comparison with calculations for the same sized He-4 clusters show some important similarities, e. g., pile up at the donut ring position but altogether a more diffuse, less anisotropic structure. These results are discussed in the light of the recently analyzed infrared spectra measured in large pure He-3 droplets (N approximate to 1.2 x 10(4)) [B. Sartakov, J. P. Toennies, and A. F. Vilesov, J. Chem. Phys. 136, 134316 (2012)]. The moments of inertia of the 11 atom spherical shell structure, which is consistent with the experimental spectrum, lies between the predicted moments of inertia for N = 8 and N = 18 clusters. Overall the calculations reveal that the structures and energies of small doped He-3 are only slightly more diffuse and less energetic than the same He-4 clusters.
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Leal, A., Mateo, D., Pi, M., Barranco, M., & Navarro, J. (2013). The structure of mixed He-3-He-4 droplets doped with OCS: A density functional approach. J. Chem. Phys., 139(17), 174308–6pp.
Abstract: We have investigated the structure and energetics of mixed He-3-He-4 droplets doped with a carbonyl sulfide molecule within a density functional approach considering a small but finite temperature of 0.1 K. The molecule is treated as an external field to which the helium droplet is attached. The energetics and appearance of these droplets are discussed for selected numbers of helium atoms, identifying the first magic numbers of the fermionic component.
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