We determine the relative thermodynamic stability of competing homogeneously and inhomogeneously ordered ferroelectric phases of PbTiO3 using its free-energy landscape, obtained from constrained-polarization moleculardynamics simulations with a first-principles effective Hamiltonian and thermodynamic integration. While we find that the tetragonal structure is thermodynamically most stable at te...

The ability to determine the free energy of solvation for a number of small organic molecules with varying sizes and properties from the coordinate trajectory of a single simulation of a given reference state was investigated. The relative free energies were estimated from a single step perturbation using the perturbation formula. The reference state consisted of a cavity surrounded by solvent....

an analytical equation of state is applied to calculate the thermodynamic properties for argon. theequation of state is that of song and mason. it is based on a statistical-mechanical perturbation theory ofhard convex bodies and can be written as fifth-order polynomial in the density. there exist three temperaturedependentparameters: the second virial coefficient, an effective molecular volume,...

“Umbrella samplmg” has been incorporated in the thermodynamic integration method to obtain a potential of mean force by slow growth molecular-dynamics simulations. The method was tested for liquid argon, for which good agreement was obtained with a standard potential of mean force, as derived from the radial pair-correlation function. For a sodium chloride ion-pair in aqueous solution the calcu...

In order to understand many biological phenomena, it is critical to get insight into the relationship among structure, function and property of biomolecules. However, it is usually di cult to infer the relation from individual data, since we usually need to examine several databases and literatures to obtain the necessary information. It would be useful to have an integrated database where one ...

This work aimed to model the critical pressure, temperature, volume properties, and acentric factors of 6700 pure compounds based on five relevant descriptors two thermodynamic properties. To that end, four methods were used, namely, multi-linear regression (MLR), artificial neural networks (ANNs), support vector machines (SVMs) using sequential minimal optimisation (SMO), hybrid SVM with Drago...

A general and simple equation of state (EOS) is a rich source for research discussion. Experience shows that high-density matter exhibits regularities some “universal” EOSs have been established. Here, we present an ideal dense EOS symmetric to the gas by means Oettingen's dual approach. The makes no assumptions about structure is, therefore, general. Thermodynamic symmetry requires has better ...

objectives: herbal medicine is known as a valid alternative treatment. salvia reuterana, which has been used in the iranian traditional medicine, is mostly distributed in the central highlands of iran. salvia reuterana is a medicinal herb with various therapeutic usages. the aim of the present review is to take account of pharmacological properties of salvia reuterana. materials and methods: th...