The Atomistic Simulation Group headed by Professor Robin Grimes is based in the Department of Materials at Imperial College London. We use various simulation techniques to predict the atomic scale mechanisms and processes underpinning material properties in order to improve the understanding and design of new materials.

The group uses both quantum mechanical and classical pair-potential approaches to study various systems including:

  • Energy Materials:
    • Fuel cells.
    • Batteries.
    • Nuclear fuel.
    • Nuclear waste.
    • Fusion materials.
  • Semiconductors.
  • Glasses.

Latest News

Congratulations to Michael Cooper for recently completing his doctorate in materials research

We would like to congratulate Michael Cooper who was successful in the recent defence of his thesis entitled Atomic Scale Simulation of Irradiated Nuclear Fuel. His work focused on using static and molecular dynamics calculations to study the role of temperature and non-stoichiometry in conventional and advanced nuclear fuels. The project culminated in the development of a many-body potential model that was used to study the behaviour of mixed actinide oxide systems.

Dr. Michael Cooper
Dr. Michael Cooper

We are pleased to announce that Dr. Michael Cooper has given us permission to make his thesis available in PDF form on our theses page. Click here to access the thesis.

New Paper - "Effects of Gallium Doping in Garnet-Type Li₇La₃Zr₂O₁₂ Solid Electrolytes"

The accepted manuscript of our new paper on gallium doping in LLZrO battery materials is now available online:

Percolation Pathways in LLZrO

The paper is the result of an ongoing collaboration between the group and Dr. Randy Jalem. Randy originally spent several months with us at Imperial whilst visiting us as a PhD student from Nagoya Institute of Technology (Japan) and we would like to thank him and the other authors for all their hard work in bringing this to completion.

Research highlights:

  • LLZrO is a candidate for use as solid electrolytes in battery applications.
  • The effects of Ga doping on the structure are considered.
  • Ga is found to stabilise the cubic phase.
  • The connectivity of Li percolation networks in LLZrO are visualised.

Read more…

New Paper - "Thermophysical properties and oxygen transport in the (Uₓ,Pu₁₋ₓ)O₂ lattice"

Our latest paper is now available from the Journal of Nuclear Materials:

In this paper we build upon a recent body of work using a many-body potential approach (see potentials page) to investigate the thermophysical and diffusion properties of actinide oxides. Using an updated version of the PuO2 parameter set we have studied the thermal expansion, specific heat capacity, oxygen diffusion and the oxygen point defect energies of (Ux,Pu1−x)O2. The results shows that the non-uniform cation lattice has a much smaller effect on the oxygen diffusion in (Ux,Pu1-x)O2 compared to (Ux,Th1-x)O2. This is expained in terms of the lattice parameter missmatch between the end member oxides and the role this plays in the defect energies.

Read more…

Potential Update - Modification to PuO₂ parameters enabling the reproduction of the melting point

In this update to our actinide potential model, adjustments have been made to the PuO₂ parameter set that enable the potential to reproduce the experimentally observed melting point.

The new parameters are reported on the actinide potential website and have been used in a recent study on (U,Pu)O₂ mixed oxides that is accepted for publication in the journal of nuclear materials.

Visit the actinides potential page for more information.

Preprint of New Paper Now available: "From solid solution to cluster formation of Fe and Cr in α-Zr"

Our latest paper on alloying additions in Zr is now available as a pre-print on arXiv:

  • P.A. Burr, M.R. Wenman, B. Gault, M.P. Moody, M.Ivermark, M.J.D. Rushton, M. Preuss, L. Edwards and R.W. Grimes, “From solid solution to cluster formation of Fe and Cr in α-Zr”, arXiv preprint (2015). PDF

By combining ab-initio simulations with advanced experimental techniques we investigate the microstructural change of Zr alloys under irradiation Zr alloys are used as nuclear fuel cladding, and their integrity is crucial for the safe production of nuclear power. Of particular concern is the increase in corrosion that is observed when Fe and Cr particles (alloys additions) are dissolved. Dissolution of these particles is related to neutron irradiation, but the mechanisms by which this occurs is still unknown.

Read more…

New Paper - "Prediction and Characterisation of Radiation Damage in Fluorapatite"

Our latest paper is now available from the Journal of Materials Chemistry A site:

In this paper we performed threshold displacement energy calculations and full damage cascades for the fluorapatite structure using molecular dynamics in conjunction with effective pair potentials. Fluorapatite is being considered as a host for the long term immobilisation of halide bearing nuclear wastes. As a result it is important to understand how the apatite structure withstands and recovers from radiation damage. Of particular interest were the structural changes noted in our damaged structures: phosphate polyhedra were found to form polymer chains, typical of phosphate glasses, that were interwoven with the calcium metaprisms forming the backbone of the apatite structure. The coincidence of these amorphous and crystalline features should help in our further understanding of the long term durability of this material.

Read more…

New Paper - "Genetics of superionic conductivity in lithium lanthanum titanates"

We pleased to announce the publication of our new paper on lithium diffusion within lithium lanthanum titanate:

Lithium lanthanum titanate (LLTO) is a material that shows high lithium diffusivity even at room temperature, this makes it of considerable interest for battery applications. In the present paper we set out to try and understand how the arrangement of lanthanum atoms within this material leads to LLTO’s beneficial properties. This was achieved by using a genetic algorithm to search for configurations with particularly high diffusivities. These were then examined to see what could be gleaned from their structure in order to unlock the key to LLTO’s beneficial properties. The paper can be found here.

Read more…

New Paper - "Thermal conductivity and energetic recoils in UO₂ using a many-body potential model"

We are please to announce a new publication in collaboration with ANSTO on the effect of radiation damage on the thermal conductivity of UO2 using our recently developed many-body actinide oxide potential.

A comparison of the damage profile predicted by the many-body potential is made against previous potential models. A significant degradation in thermal conductivity is then predicted as a consequence. The conductivity of amorphous UO2 is also calculated.

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