Subject Areas: Chemistry and Materials  Earth Sciences and Environment  Engineering and Energy  Fundamental physics  Mathematics and Computer Science  All 
Surface oxygen and magnesium ions are shown as blue and dark green spheres, respectively

Scaling up and coupling adaptive kinetic Monte Carlo with large-scale DFT

ARCHER2-eCSE05-04 : Prof Chris-Kriton Skylaris (University of Southampton)

Subject Area: Chemistry and Materials          Published : 2023-09-04

Diffusion of atoms and ions in solid state materials is essential for the function of products such as batteries, fuel cells and magnetic materials. Understanding atomic and/or ionic diffusion is therefore essential for the design and controlled manufacture of novel materials. However, computational techniques to study and analyse solid state diffusion are limited. The adaptive kinetic Monte Carlo method (aKMC) based on empirical potentials allows for material properties to be calculated efficiently, but it has clear limitations in its accuracy for certain chemical processes. In contrast, Density Functional Theory (DFT) calculations overcome these limitations, but are computationally more expensive. The recent availability of large numbers of cores on ARCHER2 provides an opportunity to combine these two approaches and develop methodologies capable of harnessing in excess of 100,000 cores. This eCSE project developed an interface to combine an aKMC program (ACDC) and a linear-scaling DFT program (ONETEP), making it possible to undertake large-scale aKMC simulations with a higher degree of accuracy than was previously possible. Read more...

Improvements in parallel high performance computing algorithms enable the simulation of hole formation in core electronic states and the prediction of x-ray photoemission spectroscopy for large scale nanostructured systems.

Relativistic all-electron orbital-constrained Density Functional Theory to simulate x-ray photoemission and absorption spectroscopy

ARCHER2-eCSE04-03 : Prof Reinhard Maurer (University of Warwick)

Subject Area: Chemistry and Materials          Published : 2023-10-26

X-ray photoemission spectroscopy (XPS) is one of the most important materials characterization techniques that are used in fundamental research and industrial quality control. FHI-aims is a software package for computational molecular and materials science that provides advanced XPS simulation capabilities. It is used to simulate the chemical and physical properties of atoms, molecules, nanostructures, solids, and surfaces. Such simulations allow researchers to discover new materials, which may be stronger, cheaper or more durable than existing materials. FHI-aims can run efficiently on anything from a laptop to a supercomputer with tens of thousands of cores. However, the section of the code used for carrying out core-hole calculations was outdated and inefficient. The work done in this eCSE project has brought that part of the code up to date, so that it is now more efficient, better documented, and easier to maintain. These changes will significantly enhance the simulation of core-level spectroscopy, enabling the simulating of bigger and more detailed systems in future. The changes will also allow a much broader range of researchers to work on these types of simulations, thus ultimately enabling new scientific discoveries. Read more...

An electrostatic potential map for two interacting water molecules, overlaid with the atoms, as exported from FHI-aims using the Atomic Simulation Interface.

Realising a modular data interface to couple quantum mechanical calculators with external data-driven workflows

ARCHER2-eCSE03-10 : Dr Andrew Logsdail (Cardiff University)

Subject Area: Chemistry and Materials          Published : 2022-10-07

Electronic structure calculations are the workhorse of modern computational chemistry, allowing for the prediction of information for a range of vital societal applications, such as drug efficacy, composition of new solar cells, or environmental impact of pollutants. However, the intrinsically complicated nature of electron interactions leads to a great variety of computational chemistry software. Complex interoperation between computer codes can slow the progress of research. To address this, a new applications programming interface, Atomic Simulation Interface (ASI), was developed and then implemented in established electronic structure software packages. This offers a unified and efficient way to export and import large data structures used in electronic structure calculations and for classical molecular dynamics simulations. Read more...

Schematic of client/server configuration.

Support for advanced transition state search techniques in CASTEP

ARCHER2-eCSE02-04 : Dr James R Kermode (University of Warwick)

Subject Area: Chemistry and Materials          Published : 2022-09-30

The CASTEP density functional theory code is a UK flagship code, specialised for solid materials, and is heavily used on ARCHER2 (300-400 active users). While support for obtaining the ground-state electronic and atomic configurations is now very good, computing transition states, reaction rates, and exploring free energy barriers with enhanced sampling were relatively poorly supported before this eCSE was completed, despite their importance for a wide range of chemistry and materials science applications. We have implemented two key new features in the CASTEP code to address these issues: (i) support for the widely used nudged elastic band (NEB) transition state search tool, augmented by a state-of-the-art robust optimizer; (ii) an interface to the i-PI universal force engine, which allows CASTEP to be connected efficiently to a range of external codes with enhanced sampling capabilities. The new tools will aid in reconciling experimental observations with atomic-scale behaviour, helping to guide and interpret future experiments. Read more...

Improving the performance of DL_MONTE for large-scale simulations

Improving the performance of DL_MONTE for large-scale simulations

ARCHER2-eCSE01-19 : Prof Steve Parker (University of Bath)

Subject Area: Chemistry and Materials          Published : 2022-11-23

Monte Carlo molecular simulation (MCMS) entails using random numbers to calculate properties of solids or fluids at the atomic scale. It is the method of choice for studying various physical phenomena of key relevance to technology: common applications include quantifying the amount of a gas which adsorbs to a surface or material; and calculating the atomic-scale properties of fluids and mixtures. There is an insatiable demand for computer simulation to be able to model more complex systems, e.g. systems comprised of more atoms, or more complex molecules. Motivated by this, this project has enabled an open-source MCMS computer program, DL_MONTE, to simulate significantly more complex systems than it could previously. Read more...

Achieving the sustainability and scalability of numeric-atomic-orbital-based linear response and electron-phonon functionality in FHI-aims

ARCHER2-eCSE01-16 : Dr Reinhard Maurer (University of Warwick)

Subject Area: Chemistry and Materials          Published : 2022-10-03

Most calculations run on ARCHER2 will employ electronic structure software packages, which are designed to solve the Schrödinger equation for molecules and materials to obtain their ground state properties. FHI-aims is one such software package, designed to be efficient when running everything from small calculations on standard laptops to huge calculations involving millions of atoms on the largest High Performance Computing systems such as ARCHER2. It is of wide interest to also calculate how molecules and materials respond to atomic displacements, or to electric and magnetic fields. This is possible using density functional perturbation theory (DFPT). A portion of the existing DFPT infrastructure within FHI-aims has been overhauled within this project, to make it more modular, intuitive, scalable, and user and developer friendly. These changes will help researchers to discover and design the next generation of materials more quickly, more cheaply, and more efficiently. Read more...

Snapshots of the fractional coverages of the activator species X* (panels a, b, c) and the inhibitor species Y*

Zacros Software Package Development: Towards Petascale Kinetic Monte Carlo Simulations with the Time-Warp Algorithm

ARCHER2-eCSE01-13 : Dr Michail Stamatakis (University College London)

Subject Area: Chemistry and Materials          Published : 2023-03-02

The chemical industry underpins virtually all sectors of the economy, from healthcare to construction. Catalytic materials, which accelerate reactions, are essential to this industry. Yet discovering catalytic materials and building catalytic processes is non-trivial. Theory and simulation can guide such efforts by delivering fundamental understanding of catalytic function. Zacros is a computational code that simulates chemical events on catalytic surfaces and enables scientists to understand how catalysts accelerate chemical reactions. This eCSE project investigated how the performance of the code is affected by different user-tuneable parameters that affect the efficiency of the parallel algorithm implemented in Zacros. The most important parameter affecting the efficiency of a run was thus identified, and tools were developed that allow users to optimise it for the systems they would be interested in simulating. The improvements made to the code will facilitate further development of improved algorithms and new features in the future. Read more...

Difference in the electronic density of an organic molecule in a solvated environment compared to in vacuum.

CASTEP Solvation Forces

ARCHER2-eCSE01-09 : Prof Matt Probert (University of York)

Subject Area: Chemistry and Materials          Published : 2023-02-08

Density-functional theory (DFT) is a quantum mechanical modelling method which is widely used in physics, chemistry and materials science to study the properties of materials where electrons dictate their behaviour. CASTEP is a UK flagship code which uses DFT to simulate a wide range of properties of materials, such as structure at the atomic level or the vibrational properties of the material. It is one of the most used codes on ARCHER2. Prior to this eCSE project, CASTEP was well adapted to investigating electronic and atomic configurations in solid materials, but not so well suited to investigating isolated molecules, or molecules in solvent, for which there is a wide range of chemistry and materials science applications. The aim of this eCSE project was to add new functionality to CASTEP to address this shortcoming, building on the work carried out in a previous ARCHER eCSE project. The result enables CASTEP users to accurately simulate molecules in solvent, without the cost of explicit solvent molecules. This will therefore open wider avenues of research with CASTEP, for instance, the study of pharmaceutical compounds and future battery designs. Read more...