TYC Symposium: Batteries - THOMAS YOUNG CENTRE

Marie-Liesse Doublet, Montpelier - The Mirage of Anionic Redox for High-Energy Batteries Alexander Squires, Birmingham - Mixed-anion NaTaOxCl6-2x oxychlorides: From crystalline to amorphous networks f...

thomasyoungcentre.org

Guidelines for robust and reproducible point defect simulations in crystals

Many physical properties of functional materials are governed by their impurities rather than their bulk characteristics. Defects in crystals can activate electronic and ionic conductivity, create act...

chemrxiv.org

Intrinsic point defect tolerance in selenium for indoor and tandem photovoltaics

Selenium has reemerged as a promising absorber material for tandem and indoor photovoltaic (PV) devices due to its elemental simplicity, unique structural features, and wide band gap. However, despite...

pubs.rsc.org

On the Estimation of Centre of Mass in Periodic Systems

Calculation of the centre of mass of a group of particles in a periodically-repeating cell is an important aspect of chemical and physical simulation. One popular approach, described by Bai and Breen,...

arxiv.org

Accurate Estimation of Diffusion Coefficients and their Uncertainties from Computer Simulation

Self-diffusion coefficients, D*, are routinely estimated from molecular dynamics simulations by fitting a linear model to the observed mean squared displacements (MSDs) of mobile species. MSDs derived from simulations exhibit statistical noise that causes uncertainty in the resulting estimate of D*. An optimal scheme for estimating D* minimizes this uncertainty, i.e., it will have high statistical efficiency, and also gives an accurate estimate of the uncertainty itself. We present a scheme for estimating D* from a single simulation trajectory with a high statistical efficiency and accurately estimating the uncertainty in the predicted value. The statistical distribution of MSDs observable from a given simulation is modeled as a multivariate normal distribution using an analytical covariance matrix for an equivalent system of freely diffusing particles, which we parametrize from the available simulation data. We use Bayesian regression to sample the distribution of linear models that are compatible with this multivariate normal distribution to obtain a statistically efficient estimate of D* and an accurate estimate of the associated statistical uncertainty.

doi.org