64 research outputs found
Performance of dispersion-corrected density functional theory for thermochemistry and non-covalent interactions
Nonmonotonic dependence of the absolute entropy on temperature in supercooled Stillinger-Weber silicon
Using a recently developed thermodynamic integration method, we compute the
precise values of the excess Gibbs free energy (G^e) of the high density liquid
(HDL) phase with respect to the crystalline phase at different temperatures (T)
in the supercooled region of the Stillinger-Weber (SW) silicon [F. H.
Stillinger and T. A. Weber, Phys. Rev. B. 32, 5262 (1985)]. Based on the slope
of G^e with respect to T, we find that the absolute entropy of the HDL phase
increases as its enthalpy changes from the equilibrium value at T \ge 1065 K to
the value corresponding to a non-equilibrium state at 1060 K. We find that the
volume distribution in the equilibrium HDL phases become progressively broader
as the temperature is reduced to 1060 K, exhibiting van-der-Waals (VDW) loop in
the pressure-volume curves. Our results provides insight into the thermodynamic
cause of the transition from the HDL phase to the low density phases in SW
silicon, observed in earlier studies near 1060 K at zero pressure.Comment: This version is accepted for publication in Journal of Statistical
Physics (11 figures, 1 table
Accurate Treatment of Large Supramolecular Complexes by Double-Hybrid Density Functionals Coupled with Nonlocal van der Waals Corrections
In this work, we present a thorough assessment of the performance of some representative double-hybrid density functionals (revPBE0-DH-NL and B2PLYP-NL) as well as their parent hybrid and GGA counterparts, in combination with the most modern version of the nonlocal (NL) van der Waals correction to describe very large weakly interacting molecular systems dominated by noncovalent interactions. Prior to the assessment, an accurate and homogeneous set of reference interaction energies was computed for the supramolecular complexes constituting the L7 and S12L data sets by using the novel, precise, and efficient DLPNO-CCSD(T) method at the complete basis set limit (CBS). The correction of the basis set superposition error and the inclusion of the deformation energies (for the S12L set) have been crucial for obtaining precise DLPNO-CCSD(T)/CBS interaction energies. Among the density functionals evaluated, the double-hybrid revPBE0-DH-NL and B2PLYP-NL with the three-body dispersion correction provide remarkably accurate association energies very close to the chemical accuracy. Overall, the NL van der Waals approach combined with proper density functionals can be seen as an accurate and affordable computational tool for the modeling of large weakly bonded supramolecular systems.Financial support by the “Ministerio de Economía y Competitividad” (MINECO) of Spain and European FEDER funds through projects CTQ2011-27253 and CTQ2012-31914 is acknowledged. The support of the Generalitat Valenciana (Prometeo/2012/053) is also acknowledged. J.A. thanks the EU for the FP7-PEOPLE-2012-IEF-329513 grant. J.C. acknowledges the “Ministerio de Educación, Cultura y Deporte” (MECD) of Spain for a predoctoral FPU grant
Reflections on intersectionality: a journey through the worlds of migration research, policy and advocacy
Fruit and vegetable consumption among 3–5-year-old Finnish children and their parents : is there an association?
This study investigated the association between the home food environment and the consumption frequency of raw and cooked vegetables, berries and fruit among 3–5-year-old children and their mothers and fathers. The target group consisted of 3–5-year-old children (N=114) attending public early childhood education and care, and their parents (N=100). Cross-sectional data were collected from the parents with questionnaires assessing the home food environment, children and parents’ vegetable, berry and fruit consumption, and food neophobia. Linear mixed-effects models and principal component analysis were used to examine the association of parental consumption and the home food environment with children’s vegetable, berry and fruit consumption. The results showed low consumption of fruit and vegetables among 3–5-year-old children and their mothers and fathers. Maternal consumption was associated with children’s raw and cooked vegetable, berry and fruit consumption, whereas paternal consumption was only associated with cooked vegetables. This study identified that home food environment factors influencing children’s consumption habits vary for raw and cooked vegetables, berries and fruit.peerReviewe
Response to Martin Seeleib-Kaiser: Migration, social policy and power in historical perspective
Evaluation of the European population intake fractions for European and Finnish anthropogenic primary fine particulate
Towards More Inclusive Protection: A Comparative Analysis of the Political Process and Socio-Economic Impact of Pension Re-Reforms in Argentina and Chile
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