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The dielectric properties of the hydrogen disordered hexagonal phase (Ih) of water ice have been computed using density functional theory (DFT) based Monte Carlo simulations in the isobaric-isothermal ensemble. Temperature dependent data yield a fit for the Curie-Weiss law of the system and hence a prediction of the temperature of the phase transition from the Ih phase to the hydrogen ordered ice XI phase. Direct simulations around the phase transition temperature confirm and refine the predicted phase transition temperatures and provide data for further properties, such as the linear thermal expansion coefficient. Results have been obtained with both hybrid and semilocal density functionals, which yields insight in the performance of the electronic structure method. In particular, the hybrid functional yields significantly more realistic dielectric constants than the semilocal variant, namely ε ≈ 116 as opposed to ε ≈ 151 at 273 K (εexperiment = 95). This can be attributed to the tendency of semilocal functionals to be biased to configurations with a large dipole moment, and their overestimation of the dipole moments of these configurations. This is also reflected in the estimates of the Ih/XI transition temperature, which is 70-80 and 90-100 K for the hybrid and semilocal functional respectively. DFT based sampling of the millions of configurations necessary for this work has been enabled by a Tree Monte Carlo algorithm, designed for massively parallel computers.
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Name: The journal of physical chemistry. B
The dielectric properties of multilayer GaS films have been investigated using a Berry phase method and a density functional perturbation theory approach. A linear relationship has been observed betwe...
Molecules in crystals often suffer from severe limitations on their dynamic processes, especially on those involving large structural changes. Crystalline compounds, therefore, usually fail to realize...
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A system of hard rectangles of size m×mk on a square lattice undergoes three entropy-driven phase transitions with increasing density for large-enough aspect ratio k: first from a low-density isotrop...
The purpose of this research is to investigate how using different methods to reduce the energy density of entrees affects daily energy intake in adults. It is hypothesized that reducing t...
This study will investigate the prevalence and extent of both metabolic and psychosocial changes associated with the menopause transition over 1 year among women with HIV compared to women...
The study will evaluate whether the blood concentrations of eletriptan administered using two test formulations of oral disintegrating tablets are comparable to those observed with the sta...
Women undergoing surgical menopause often experience marked menopausal side effects but are reluctant to use estrogen or other female hormones to ease the transition to menopause because o...
The principal objective of this research is the evaluation of the effect of mineralized water consumption upon evolution of LDL Cholesterol and triglycerides, compared to a low mineralized...
A technique of measuring the dielectric properties of materials, which vary over a range of frequencies depending on the physical properties of the material. The technique involves measuring, over a range of frequencies, ELECTRICAL IMPEDANCE and phase shift of an electric field as it passes through the material.
A cyclin subtype that is transported into the CELL NUCLEUS at the end of the G2 PHASE. It stimulates the G2/M phase transition by activating CDC2 PROTEIN KINASE.
Members of the src-family tyrosine kinases that are activated during the transition from G2 PHASE to M PHASE of the CELL CYCLE. It is highly homologous to PROTO-ONCOGENE PROTEIN PP60(C-SRC).
Conjugation of exogenous substances with various hydrophilic substituents to form water soluble products that are excretable in URINE. Phase II modifications include GLUTATHIONE; ACYLATION; and AMINATION. Phase II enzymes include GLUTATHIONE TRANSFERASE and GLUCURONOSYLTRANSFERASE. In a sense these reactions detoxify phase I reaction products.
A change of a substance from one form or state to another.