New methods for simulations of complex actinide materials based on relativistic linear-scaling quantum mechanics

TMCS is an EPSRC Centre for Doctoral Training operated by the Universities of Oxford, Bristol and Southampton.
In year one you will be based in Oxford with a cohort of around 12–15 other TMCS students, and will receive in-depth training in fundamental theory, software development, and chemical applications, delivered by academics from all three Universities. Successful completion of the year-one program leads to the award of an Oxford MSc, and progression to the 3-year PhD project based in Southampton, and will include close collaboration with the industrial sponsors.

This project will offer unique exposure to both academic and industrial research environments and is ideally suited to applicants who wish to make an impact in problems of real practical relevance.

The computational simulation of chemical reactions in materials requires an accurate and explicit description of their electrons. This can be achieved by quantum mechanical calculations from first principles, with methods such as Density Functional Theory (DFT). DFT calculations have typically been limited to tens of atoms due to the steep increase of the computational effort, which scales with the third power in the number of atoms. Recent developments in the theory and methods have led to “linear-scaling” reformulations of DFT, which allow calculations with thousands of atoms. While quantum mechanics from first principles does not depend on empirical parameters and as a result, it can be used on any material, it is no longer chemically accurate when applied to materials containing heavy f-block elements such as actinides. The reason for this failure is the lack of essential relativistic corrections needed to provide an accurate description of the electronic structure as relativistic effects heavily influence the geometries and chemistry of these compounds and cannot be ignored. Various levels of such relativistic corrections have been implemented in conventional DFT programs but much less is available within linear-scaling DFT formulations and as a result, simulations on complex actinide-containing materials are very challenging.

The goal of this PhD project is to address this grand challenge by developing and validating within the ONETEP linear-scaling DFT program the capabilities that are required for accurate large-scale DFT calculations on actinide compounds. This will involve the implementation of a hierarchy of relativistic methods of increasing sophistication, which will need to be reformulated and expressed within the localised non-orthogonal orbital framework on which the ONETEP method is based. The developed methodologies will be validated against experimental and computational data – provided by the industry partners. Many of these developments will be novel in the area of DFT codes for large-scale calculations and therefore this project represents a great opportunity to make an impact in the field of electronic structure theory method development.

This project will be carried out in the group of Professor Chris-Kriton Skylaris at the University of Southampton and will be co-supervised by Professor Skylaris and by industrial collaborators. If you wish to discuss any details of the project informally, please contact Professor Chris-Kriton Skylaris, Email: [Email Address Removed] , Tel: +44 (0) 2380 59 9381.