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Tim Duignan

@timothyduignan.bsky.social
531 followers 809 following 101 posts

Researcher at Orbital Materials. Working on molecular simulation with ML for chemical engineering applications.

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Tim Duignan @timothyduignan.bsky.social · 20/10/2025
In practice that means use Omol or Omat standards unless you really need to use something different I guess. As those are the biggest data sets out there?
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Tim Duignan @timothyduignan.bsky.social · 20/10/2025
When generating training data on specific systems the MLIP/NNP community needs to get organized and agree on one particular level of theory, settings and data storage standards as much as possible so we can pool all the data for training foundation/universal models right?
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Tim Duignan @timothyduignan.bsky.social · 10/10/2025
I have no idea how long this period will last. But it may go faster than we realise. I have no idea what comes after. But I know I really don't want to miss it.
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Tim Duignan @timothyduignan.bsky.social · 10/10/2025
We may be just at the beginning of a period where individual scientists working with a team of AI agents will be able to get an immense amount done. Particularly for computational tasks that don't require physical experiments.
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Tim Duignan @timothyduignan.bsky.social · 10/10/2025
When agentic AI started popping up I remember thinking, yeah that is the logical next step but we're not there yet. Its a several years away, well I think its here now and it came much faster then I expected. It's still early days but seems it will have a profound impact.
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Tim Duignan @timothyduignan.bsky.social · 09/10/2025
We're beginning to understand the properties and formation of this crucially important complex material (the SEI) in great detail using NNPs/MLIPs. Now we can start using that knowledge to really design and engineer it to perfection. Exciting times ahead!
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Tim Duignan @timothyduignan.bsky.social · 09/10/2025
Then another one from De Angelis et al. showing a very interesting collective ring diffusion process involving six lithium ions in LiF a key component of the SEI. (chemrxiv.org/engage/chemr...)
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Tim Duignan @timothyduignan.bsky.social · 09/10/2025
I actually observed these pairs in water a while ago with an NNP and worried a lot that they were a hallucination as it is very counter intuitive that two such small cations would pair like that. But looks like it’s real, and really important! (iopscience.iop.org/article/10.1...)
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Tim Duignan @timothyduignan.bsky.social · 09/10/2025
James Stevenson et al. show (with experimental evidence) that lithium cations can pair up in the battery solvent and that these pairs are what form the SEI. (chemrxiv.org/engage/chemr...)
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Tim Duignan @timothyduignan.bsky.social · 09/10/2025
The SEI is the thin layer that forms between the surface of the graphite electrode and the liquid electrolyte in a battery and without it lithium ion batteries wouldn’t be possible as the graphite quickly exfoliates. Despite the its importance we know very little about it.
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Tim Duignan @timothyduignan.bsky.social · 09/10/2025
Couple of very nice new papers on understanding the SEI formation in lithium ion batteries using neural network/machine learning interatomic potentials (NNPs/MLIPs).
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Tim Duignan @timothyduignan.bsky.social · 18/09/2025
Universal machine learning forcefields beating tailor made classical potentials for zeolites quite convincingly. Great to see all these benchmarking papers! Again demonstrates accurate training data + speed should be key focus now. arxiv.org/abs/2509.07417
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Tim Duignan @timothyduignan.bsky.social · 09/09/2025
That’s basically the same machine-learning problem NNPs are already solving and theres already many demonstrations they work well for this purpose. Some tricky problems like coupling the coarse-grained and all-atom levels remain, but that seems solvable.
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Tim Duignan @timothyduignan.bsky.social · 09/09/2025
But yeah at some point you have to use the nano second scale simulations to train coarse grained models integrate out the short range high frequency motions and learn the free energy surface.
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Tim Duignan @timothyduignan.bsky.social · 09/09/2025
Which means you can brute force carbonic anhydrase and potassium ion channels etc. easily which are at the fast end admittedly but then with some smart enhanced sampling like replica exchange/meta dynamics it should get you the rest of the way to many important discoveries.
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Tim Duignan @timothyduignan.bsky.social · 09/09/2025
With distilled, optimized NNPs, and new generation of GPU clusters, should be able to approach classical speeds (100s ns/day).
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Tim Duignan @timothyduignan.bsky.social · 09/09/2025
I think neural network potentials are the eventual pathway to a virtual cell. The accuracy/memory are quite close to where you need them. Timescale is the last real hurdle. But we can port decades of great tools from classical FFs, so it’s becoming more of an engineering problem now.
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Tim Duignan @timothyduignan.bsky.social · 08/09/2025
arxiv.org/pdf/2508.15614 This is right and it's a big deal. Been waiting my whole career for this point. So many things to simulate!
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Tim Duignan @timothyduignan.bsky.social · 02/09/2025
Another very interesting benchmarking paper on NNPs. lnkd.in/gWbcTQw8 It seems the models are pretty much there. Very exciting times as these new large datasets continue to be built. Always need more though!
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Tim Duignan @timothyduignan.bsky.social · 29/08/2025
There’s examples of how to run Md in the examples folder github.com/orbital-mate... to get a solvated protein there download the pdb and use PDB2PQR to add hydrogens and solvent with parmed or find a classical Md paper where they’ve already done this
github.com
GitHub - orbital-materials/orb-models: ORB forcefield models from Orbital Materials
ORB forcefield models from Orbital Materials. Contribute to orbital-materials/orb-models development by creating an account on GitHub.
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Tim Duignan @timothyduignan.bsky.social · 29/08/2025
Nice recent example this is an important problem for Pharma: chemrxiv.org/engage/chemr... The new models should be much better at this
chemrxiv.org
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Tim Duignan @timothyduignan.bsky.social · 29/08/2025
MD= molecular dynamics and is basically just a direct simulation of how the molecules behave we haven't been able to do this accurately for any interesting systems accurately enough until now, which we now can because of these models.
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Tim Duignan @timothyduignan.bsky.social · 29/08/2025
The main limitation is there are many processes that occur on too long a timescales but we can build big molecular dynamics data sets with this model and then train coarse grained models on those to get to the longer time/spatial scales.
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Tim Duignan @timothyduignan.bsky.social · 29/08/2025
Many people are already doing amazing science with custom built NNPs for many substances. The idea is now they can skip making the training data and building the model and go straight to doing science.
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Tim Duignan @timothyduignan.bsky.social · 29/08/2025
It kind of has too many applications to list. But generally for any substance you want to know its structural, kinetic and thermodynamic properties. All of them can be derived from MD in principle.
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Tim Duignan @timothyduignan.bsky.social · 28/08/2025
For generations people have been dreaming of simulating real complex chemistry like enzymes and MOFs starting from nothing but quantum mechanics. Well I really think it's here.
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Tim Duignan @timothyduignan.bsky.social · 28/08/2025
This means it should be possible to look at crucially important angstrom/picosecond scale phenomena like the hydrogen bond network of water and how it controls reaction dynamics etc. where we really lack adequate tools.
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Tim Duignan @timothyduignan.bsky.social · 28/08/2025
I'm particularly excited about how close the structure stays to experiment, with no constraints, even though the training data doesn't contain a single protein.
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Tim Duignan @timothyduignan.bsky.social · 28/08/2025
And you can look at huge systems with them. Like the 20,000 atoms solvated carbonic anhydrase enzyme with many different complex interactions going on. You can do hundreds of thousands of calculations on it with a single GPU in a few days, with no unphysical behaviour.
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Tim Duignan @timothyduignan.bsky.social · 28/08/2025
It's amazing to me that you can just pick general purpose DFT validation sets and benchmark them like they are a DFT functional and they will normally do a great job out of the box. Often similar to a dispersion corrected GGA or better but orders of magnitude faster.
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Tim Duignan @timothyduignan.bsky.social · 28/08/2025
Another remarkable jump in accuracy with these new OrbMol models for simulating chemistry. For example, they now quantitatively reproduce the structure of water. But they should be just as applicable for studying a vast range of different liquids.
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Tim Duignan @timothyduignan.bsky.social · 24/07/2025
Another nice benchmarking paper highlighting the rapid exciting progress of universal MLIPS/NNPs: www.arxiv.org/abs/2507.11806
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Tim Duignan @timothyduignan.bsky.social · 23/06/2025
Love this combination of LLMs and NNPs, a powerful pair of tools. www.sciencedirect.com/science/arti... Also wonderful to see people picking up Orb so quickly and getting good results!
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Tim Duignan @timothyduignan.bsky.social · 19/06/2025
This is excellent! arxiv.org/abs/2506.14492
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Reposted by Tim Duignan
Jan Hermann @hrmnn.net · 18/06/2025
🚀 After two+ years of intense research, we’re thrilled to introduce Skala — a scalable deep learning density functional that hits chemical accuracy on atomization energies and matches hybrid-level accuracy on main group chemistry — all at the cost of semi-local DFT ⚛️🔥🧪🧬
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Reposted by Tim Duignan
Rianne van den Berg @riannevdberg.bsky.social · 18/06/2025
So proud of this work with our amazing team 🤩
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Tim Duignan @timothyduignan.bsky.social · 18/06/2025
Once we crack the ability to design SEIs rationally batteries will really take off. Such an exciting field! Please share any others I should read?
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Tim Duignan @timothyduignan.bsky.social · 18/06/2025
4) Finally this one studying interphase formation on lithium metal. (arxiv.org/abs/2506.10944 ) Until now we have known next to nothing about how these incredibly important layers form or even what they are composed of as they show.
arxiv.org
Coupled reaction and diffusion governing interface evolution in solid-state batteries
Understanding and controlling the atomistic-level reactions governing the formation of the solid-electrolyte interphase (SEI) is crucial for the viability of next-generation solid state batteries. How...
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Tim Duignan @timothyduignan.bsky.social · 18/06/2025
3) There is a new distillation method and code (arxiv.org/abs/2506.10956) that accelerates universal NNPs by 10 - 100 x.
arxiv.org
Distillation of atomistic foundation models across architectures and chemical domains
Machine-learned interatomic potentials have transformed computational research in the physical sciences. Recent atomistic `foundation' models have changed the field yet again: trained on many differen...
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Tim Duignan @timothyduignan.bsky.social · 18/06/2025
2) Another showing you can examine MOF break down at high temperature, which will be critical for designing new more stable ones. chemrxiv.org/engage/chemr...
chemrxiv.org
Exploring foundational machine learned potentials for treating the high temperature dynamics of metal-organic frameworks
Metal-organic framework (MOF) derived materials, formed through high temperature processes, show great potential as catalysts. However, knowledge of the structure-property relationships between the in...
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Tim Duignan @timothyduignan.bsky.social · 18/06/2025
1) First eval paper that includes Orb-v3 and has done an excellent job getting nice experimental data to compare with. It concludes: “ORB v3 stands out in many tests,” arxiv.org/abs/2506.01860
arxiv.org
Benchmarking Universal Machine Learning Interatomic Potentials for Real-Time Analysis of Inelastic Neutron Scattering Data
The accurate calculation of phonons and vibrational spectra remains a significant challenge, requiring highly precise evaluations of interatomic forces. Traditional methods based on the quantum descri...
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Tim Duignan @timothyduignan.bsky.social · 18/06/2025
So many nice NNP papers coming out now it is impossible to stay on top of them. Four very cool recent ones:
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Tim Duignan @timothyduignan.bsky.social · 27/03/2025
Feel free to email anytime
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Reposted by Tim Duignan
Joe Greener @jgreener64.bsky.social · 20/03/2025
Interesting work exploring an enzyme reaction with a machine learning potential. Looking forward to much more like this in the next few years.
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Tim Duignan @timothyduignan.bsky.social · 21/03/2025
Yeah should hopefully be possible
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Tim Duignan @timothyduignan.bsky.social · 19/03/2025
Preprint here: arxiv.org/abs/2503.13789 You can check out the trajectories yourself, i.e,: rcsb.ai/bf7e353ddf (Thanks Alexander Mathiasen) Orb itself can be found here: github.com/orbital-mate....
arxiv.org
Carbonic anhydrase II simulated with a universal neural network potential
The carbonic anhydrase II enzyme (CA II) is one of the most significant enzymes in nature, reversibly converting CO$_2$ to bicarbonate at a remarkable rate. The precise mechanism it uses to achieve th...
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Tim Duignan @timothyduignan.bsky.social · 19/03/2025
Even more surprisingly, it also suggests a new previously unreported reaction mechanism for forming bicarbonate, which actually makes a lot of sense and independent quantum chemistry show is plausible. (Done with Rowan).
arxiv.org
Carbonic anhydrase II simulated with a universal neural network potential
The carbonic anhydrase II enzyme (CA II) is one of the most significant enzymes in nature, reversibly converting CO$_2$ to bicarbonate at a remarkable rate. The precise mechanism it uses to achieve th...
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Tim Duignan @timothyduignan.bsky.social · 19/03/2025
Remarkably, despite only being trained on small crystals, it manages to spontaneously reproduce the proton relay carrying protons from the zinc-bound water to the His64 residue — a mechanism that took over a decade of careful experimental studies to unravel.
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Tim Duignan @timothyduignan.bsky.social · 19/03/2025
So Orb has blown me away again. I simulated the carbonic anhydrase enzyme with it: one of the most important and well studied enzymes in biology. (It converts CO2 to bicarbonate and is involved in many diseases and could also be useful for carbon capture.)
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Tim Duignan @timothyduignan.bsky.social · 25/02/2025
(The trick is to specify brute_force_knn=False in the calculator.) This is more than an order of magnitude larger than some other universal models. I can get over 7,000 steps of molecular dynamics per day with it.
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