UK Atomic, Molecular and Optical physics R-matrix consortium (UK AMOR)

The R-matrix methodology is a UK success story. The method was originally developed to provide rigorous treatment of electron collisions with ions and atoms. It was then expanded to treat electron molecule collisions and matter in intense laser fields. Further extension to treat ultracold chemistry forms part of this proposal. The development of the software based on R-matrix methodology has received extensive support from CCPQ (and its predecessors), EPSRC and eCSE. The resulting code set is at the forefront of international atomic, molecular and optical (AMO) physics and is used by researchers world-wide. R-matrix studies have ridden successive waves of computer development and as a result are making an increasing contribution to science and technology in many areas.

UK AMOR is a new High End Computing consortium which will work in the general area of AMO physics. Problems studied using ARCHER will include:

a) The interaction of atoms and molecules with light including intense light sources. R-matrix with time-dependence (RMT) is the leading code in this area, allowing calculations at the intersection of atomic and strong-field physics. Ongoing extensions to molecules, and atoms in arbitrarily polarised laser pulses will further establish the code on the world stage. This will provide key support for exciting experimental work being performed on these physical processes.

b) Electron collisions with atoms, ions and molecules using UK codes which are widely used internationally. Calculations will focus on applications ranging from fusion plasmas to radiation damage in biological systems. For fusion we will focus on high accuracy calculations on atoms and ions, and key molecules important for fusion experiments. We will also perform high accuracy electron-molecule collisions calculations to study:
1) large systems such as molecular clusters and biomolecules where results are important for studies radiation of tracks and DNA damage.
2) processes of applied relevance for extended energy ranges,
3) processes of applied where improved models will provide more accurate scattering data
4) benchmark problems with full uncertainty quantification.
These studies are only possible using the new UKRMol(+) code and ARCHER.

c) Ultracold chemistry: this a new area of study. Codes will be developed to treat ultraslow collisions for reactive systems over deep potential wells. Such systems are characterised by complex resonance structures whose study offers unique opportunities for chemical control and insights into this fundamental process. The methodology will also be applicable to a variety of related low-energy processes such as radiative association. Calculations will be performed on systems accessible to planned state-of-the-art experiment.

The main UK AMOR impacts can be summarized as follows:

Knowledge:

(i) the provision of ARCHER time to the UK R-matrix community to interpret, guide and enable novel science with high potential for future societal and economic impact. Planned calculations touch on key experimental areas and will be performed with the needs of experimental community in mind. The main areas are:
(a) the use attosecond light to investigate and control electron dynamics. This control can be exploited to provide XUV laser light with controllable parameters and improve our understanding of reaction dynamics impacting on many different areas of science, especially in research areas involving chiral molecules, such as chemistry and biochemistry.
(b) the provision of reliable atomic physics data to fusion community and to model stellar interiors.
(c) the study of electron and positron collisions from molecules and molecular clusters of applied interest. High end calculations with these codes are increasingly replacing experiment for computation of molecular processes in plasmas and results are used for technological studies, fusion and astrophysics and, potentially, as the input for radiation track models of living systems.
(d) It is the dawn of studying chemical reactions at ultralow temperatures and, for reactions involving more than 2 atoms, there is little theoretical support. Studies in this area will focus on problems which are amenable to experiment. Potential experimental collaborators include the groups in Oxford, UCL, Nijmegen, Columbia, UCLouvain.

(ii) the continuous development of associated software made freely available to the scientific community. Free distribution of our codes maximizes their impact: thus, for example, a significant majority of calculations performed using the UKRmol electron-molecule suite are performed outside the UK.

Economic impact:

Calculations on electron - atom and - molecule processes are of applied importance, for example, for the provision of data for diagnostics calculations in magnetic fusion. Another example where molecular data is needed is Focused Electron Beam Induced Deposition (FEBID), a nanofabrication technique based on direct deposition requires understanding of electron induced break-up of precursor molecules. Many of these are big (many atom), metal containing molecules that are too electron rich to be even attempted with existing codes, but very recent developments in the UK AMOR suite will now make them possible.

Developments in the suite of codes will be shared with project partner Quantemol Ltd, an export-driven company which provides commercial companies and academic researchers expert systems for solving problems of practical importance. The company has launched two products aimed at the plasma etching industry, including Quantemol-N, an expert system which runs the UKRmol+ predecessor (UKRmol). Quantemol will adapt their Quantemol-N front end to run UKRmol+. Its increased functionality, particularly that related to molecule-light interactions, will provide Quantemol with new expansion opportunities, for example, into lighting modelling. Quantemol is currently expanding and would like to make new hires in plasma science area. Quantemol uses the codes for consultancy projects which cover a variety of areas, to populate the newly released QDB database and for direct sales. At present clients use the Quantemol-N substantially to improve the plasma etching tools but Quantemol hopes to significantly expand the market sectors it is involved in using the newest versions of the codes.

People:

UK-AMOR will train a number of young scientists in software development and high-end computing as well as give high-school and undergraduate students interested in science and computing an opportunity to experience scientific software development. The science generated as part of the project will be disseminated to wider audiences through participation in outreach events