Alex Squires
agsquires.bsky.social
Alex Squires
@agsquires.bsky.social
Group Leader in the Scanlon Materials Theory Group at UoB chemistry
Reposted by Alex Squires
Good @thomasyoungcentre.bsky.social symposium this afternoon on the modelling of battery cathodes and solid-state electrolytes.

Thanks to Marie-Liesse, Alex and Ben for coming to London and present their work.

#chemsky #compchem
October 30, 2025 at 6:44 PM
Reposted by Alex Squires
Next Thursday afternoon, 30/10, the @thomasyoungcentre.bsky.social is organising a symposium in London on modelling battery materials with as speakers Marie-Liesse Doublet (Montpellier), Alex Squires (Birmingham) and Benjamin Morgan (Bath).
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
October 24, 2025 at 1:59 PM
Reposted by Alex Squires
Defect calculations have many pitfalls and key considerations for achieving good accuracy 🎯

In this perspective, we discuss these issues, how to avoid and how we can make defect simulations more reproducible – particularly important with more ML developments! 📊

chemrxiv.org/engage/chemr...
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
September 29, 2025 at 12:23 PM
Reposted by Alex Squires
Intrinsic & extrinsic (dopant) defect chemistry of trigonal Selenium for PV, incl metastable states & non-radiative recombination ⬇️

Combined theory & expt analysis, we find an intrinsic tolerance to 𝘱𝘰𝘪𝘯𝘵 defects, with GBs/interfaces the limiting factor for PV 📈
pubs.rsc.org/en/Content/A...
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
April 15, 2025 at 1:16 PM
Very gracious for David to let me off the leash on this one. Kick-started an agyrodite obsession (though I may be a bit late to the party on this one)
March 13, 2025 at 8:26 PM
Reposted by Alex Squires
@agsquires.bsky.social has just published this lovely work with wolfgang zeier! pubs.acs.org/doi/10.1021/... @uobchemistry.bsky.social
March 13, 2025 at 8:12 PM
Seán's efforts with doped are heroic. I can only apologise for some of my commits 👀

But it's now never been easier to start charging about in chemical potential space to find out what your defects are doing!
The latest version of 𝙙𝙤𝙥𝙚𝙙 (and 𝑺𝒉𝒂𝒌𝒆𝑵𝑩𝒓𝒆𝒂𝒌), our defect modelling python packages, have been released!

Incl:
- Major efficiency updates
- Advanced defect/carrier thermodynamics w/custom constraints
- Auto shallow defect handling
- CC diagram generation
...🧵👇
February 4, 2025 at 7:29 PM
Reposted by Alex Squires
Excited to share Harry Richardson’s first paper, which has gone live on arXiv. If you have ever calculated the centre of mass of a simulated molecule, I would recommend giving it a read. arxiv.org/abs/2501.14578 #compchem
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
January 27, 2025 at 9:48 AM
Reposted by Alex Squires
Ending the year with the nice closure of finally getting a long running project published. doi.org/10.1021/acs....
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
December 30, 2024 at 9:17 PM