Dielectric Properties of Water Ice, the Ice Ih/XI Phase Transition, and an Assessment of Density Functional Theory.

07:00 EST 7th January 2014 | BioPortfolio

Summary of "Dielectric Properties of Water Ice, the Ice Ih/XI Phase Transition, and an Assessment of Density Functional Theory."

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.


Journal Details

This article was published in the following journal.

Name: The journal of physical chemistry. B
ISSN: 1520-5207


DeepDyve research library

PubMed Articles [36096 Associated PubMed Articles listed on BioPortfolio]

Tunable Dielectric Responses Triggered by Dimensionality Modification in Organic-Inorganic Hybrid Phase Transition Compounds (C5H6N)CdnCl2n+1 (n = 1 and 2).

Two hybrids (C5H6N)CdCl3 (1) and (C5H6N)Cd2Cl5 (2) were synthesized by stoichiometric regulation of reactants. 1 with a one-dimensional chain-like structure shows a step-like dielectric anomaly at aro...

Successive Phase Transition, Dielectric Ordering, and Liquid Crystalline Behavior of Simple (Laurylammonium)(Phenyl Phosphates) Salts.

Successive phase transitions of three kinds of simple 1:1 organic salts of laurylammonium (LA) - phenyl (3-pyridyl) phosphate derivative were examined in terms of thermal properties, single crystal X-...

Background field functional renormalization group for absorbing state phase transitions.

We present a functional renormalization group approach for the active to inactive phase transition in directed percolation-type systems, in which the transition is approached from the active, finite d...

Classical density functional study of wetting transitions on nanopatterned surfaces.

Even simple fluids on simple substrates can exhibit very rich surface phase behaviour. To illustrate this, we consider fluid adsorption on a planar wall chemically patterned with a deep stripe of a di...

Discovering A First-order Phase Transition in Li-CeO2 System.

An in-depth understanding of (de)lithiation induced phase transition in electrode materials is crucial to grasp their structure-property relationships and provide guidance to the design of more desira...

Clinical Trials [6773 Associated Clinical Trials listed on BioPortfolio]

Utility of Cortical Bone Tissue Properties in the Assessment of Fracture Risk

The objective of this study is to determine whether a new minimally invasive method for in vivo measurement of cortical bone tissue properties can identify those who are at risk for fragil...

Reducing Energy Density by Different Methods to Decrease Energy Intake

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...

Early Detection of Lymphedema With Bio-Electrical Impedance Analysis in Patients After Breast Cancer Surgery

Bio-electrical impedance analysis and Tissue Dielectric Constant measurements are objective methods in clinical usage to detect lymphedema in early stage. The aim of this study is to revea...

Metabolic and Psychological Changes Associated With Menopause Among Women With HIV

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...

Pharmacokinetics of Two Eletriptan Oral Formulations Given With and Without Water and the Commercial Tablet Formulation Given With Water

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...

Medical and Biotech [MESH] Definitions

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.

Quick Search

DeepDyve research library

Searches Linking to this Article