Benjamin Shi

An accurate and efficient framework for modelling the surface chemistry of ionic materials - Nature Chemistry Simulating molecular adsorption on surfaces presents considerable challenges, as computational methods typically suffer from either insufficient accuracy or prohibitive computational costs. Now, with ...

A tough call? Cost vs speed. So congrats to Michaelides and all for their modelling work @natchem.nature.com that asks 'Why not both?' www.nature.com/articles/s41...
@benshi.bsky.social
@andrewrosen.bsky.social @tschaefer-sc.bsky.social @zenandrea.bsky.social @ice-group-cam.bsky.social

Basis Set Incompleteness Errors in Fixed-Node Diffusion Monte Carlo Calculations on Noncovalent Interactions Basis set incompleteness error (BSIE) is a common source of error in quantum chemistry calculations, but it has not been comprehensively studied in fixed-node Diffusion Monte Carlo (FN-DMC) calculations. FN-DMC, being a projection method, is often considered minimally affected by basis set biases. Here, we show that this assumption is not always valid. While the relative error introduced by a small basis set in the total FN-DMC energy is minor, it can become significant in binding energy (Eb) evaluations of weakly interacting systems. We systematically investigated BSIEs in FN-DMC-based Eb evaluations using the A24 data set, a well-known benchmark set of 24 noncovalently bound dimers. We found that BSIEs in FN-DMC evaluations of Eb are indeed significant when small localized basis sets, such as cc-pVDZ and cc-pVTZ, are employed. Our study shows that the aug-cc-pVTZ basis set family strikes a good balance between computational cost and BSIEs in the Eb calculations. We also found that augmenting the basis sets with diffuse orbitals, using counterpoise correction, or both, effectively mitigates BSIEs, allowing smaller basis sets such as aug-cc-pVDZ to be used.

#compchem Good read: Basis Set Incompleteness Errors in Fixed-Node Diffusion Monte Carlo Calculations on Noncovalent Interactions #compchemsky pubs.acs.org/doi/10.1021/...

Roadmap on Advancements of the FHI-aims Software Package Electronic-structure theory is the foundation of the description of materials including multiscale modeling of their properties and functions. Obviously, without sufficient accuracy at the base, relia...

The biggest paper I was ever part of appeared on arXiV today: "Roadmap on Advancements of the FHI-aims Software Package". Over 20 years of work. Immensely grateful to the 200+ people on this paper, who pushed our ability to simulate materials forward! #chemsky #compchemsky

arxiv.org/abs/2505.00125

Efficient all-electron hybrid density functionals for atomistic simulations beyond 10 000 atoms Hybrid density functional approximations (DFAs) offer compelling accuracy for ab initio electronic-structure simulations of molecules, nanosystems, and bulk mat

Yes, well - FHI-aims works. AFAIK our periodic hybrid DFT can reach systems that I haven't seen anywhere else pubs.aip.org/aip/jcp/arti... ... and in addition to much development (as always) we spent a lot of time on tutorials, webinars, etc. recently.

Is fixed-node diffusion quantum Monte Carlo reproducible? Fixed-node diffusion quantum Monte Carlo (FN-DMC) is a widely-trusted many-body method for solving the Schrödinger equation, known for its reliable predictions of material and molecular properties. Fu...

arxiv.org/abs/2501.12950 #compchem

Happy 2025!

Did you ever think whilst eating your Christmas dinner how salt dissolves? @niamhoneill.bsky.social did.

Name: Niamh
Likes: Running (jobs) 🏃‍♀️💻
Dislikes: Deionised Water 🧂❌
Most likely to: tell you all about Ireland ☘️

It has been an amazing four years in this group, sad to be leaving!

#ScienceWriting

Hello everyone 👋
We are CECAM, the European Center for Atomic and Molecular Calculations, based on the EPFL campus in Switzerland. Our aim is to foster fundamental research on computational science for societal benefit.
Discover more about us and our activities on our website: www.cecam.org

Good programming practice is good science. If you want your codes to be used by others and don't know where to start (and are using Python), then start here.

You can also check out my template: github.com/Quantum-Acce...