Castep: Advanced spectroscopies using high-performance computing

With recent theoretical and computational advances we have been able to calculate the properties of condensed matter systems from first principles. That one can even hope to do this is down to the accuracy of quantum mechanics in describing the chemical bond. Dirac's apocryphal quip that after the discovery of quantum mechanics the rest is chemistry sums it up: if one can solve the Schrodinger equation for something - an atom, a molecule, assemblies of atoms in solids or liquids - one can predict every physical property. Dirac's statement doesn't quite show how difficult doing the rest is, and it has taken great effort and ingenuity to take us to the point of calculating some of the properties of materials with reasonable accuracy. The impact of simulations on our thinking about condensed matter problems is immense. However, the CASTEP code attempt to calculate many properties of materials using only quantum mechanics (in particular, density functional theory).CASTEP is a richly featured first principles electronic structure code and as such its capabilities are numerous. Aiming to calculate any physical property of the system from first principles, the basic quantity is the total energy from which many other quantities are derived. Here we wish to develop CASTEP's range of applications further, making is valuable to a much wider range of scientists which will enable them to perform their research in a fast, reliable and accurate manner.It has been designed specifically for use on high-performance computers, being written from the ground up with a many-core architecture in mind. Castep is one of the most used codes on the UK supercomputing facility, HECToR. We aim to develop an exciting range of new spectroscopic tools that will form a close link between theoretical/computational condensed matter and experimental techniques. Interpretation of experimental spectroscopic data is not straightforward, but if software that is build on a firm, accurate theoretical foundation can be used to generate such data, then direct comparison to experiment can be performed and allow detailed interpretation of the results to be done. This is the aim of the current proposal. Throughout we will maintain the highest quality code design/implementation and testing techniques, as we have consistently done in the past. At the end of this work we will have new functionality in CASTEP that will produce new science. A further proposal (stage 2 of this call) will be used to make the code of a quality such that it can be widely used.

We have identified a number of pathways by which the outputs of the proposed research will impact more widely than the more obvious academic research implications (which is detailed in the Academic Beneficiaries section). These additional routes include both economic and educational impact. As Castep is already a well used academic and commercial code, and also widely used for teaching purposes, the impact of the current work is far reaching. We summarise it as follows: The direct economic impact of this research is the potential for commercialisation of the outputs: Accelrys Inc. (see www.accelrys.com) provide a commercially supported version of the CASTEP software to Industrial users which is licensed from the CASTEP Developers Group. Therefore the route to commercialisation already exists for this work and will be fully used. Furthermore, the Materials Studio graphical user interface is also supplied which makes for much greater each of use for the end user. The expanded functionality will both enhance the scientific capabilities for the current wide user base and, importantly, allow the expansion into new sectors of industry, for example, researchers working in areas such as magnetic capability for storage, light emitting polymers and organic light emitting diodes (OLEDs) which are the basis of next generation display technologies. A letter of support for this research from Accelrys is attached. The outputs of the research will also have indirect impact on the following groups working in the area of optical and magnetic spectroscopy. As these methods (Raman, NMR, IR, and so on) are some of the most widely used analytical techniques in chemical, bio-material and physics laboratories in industry, then any method which aids such work will be advantageous. For example, until the wide-spread use of first principles electronic structure methods in spectroscopy it was extremely difficult to identify spectral features from experiment. It is now common practice to use a combination of experimental and modeling techniques to do this. The new spectroscopic features that we will add to CASTEP will be of substantial impact in these general areas. CASTEP is also a code used for educational purposes. A significant number of researchers use the code in their post-graduate studies. The additional features added to the code-base achieved in this grant expand the use at this level, enhancing study capabilities. Of course, may of these students will eventually work in industrial research settings where experience in first-principles modelling will be advantageous. In the longer term, emergence of impact will be seen through the discovery of new technologically advanced materials. Using CASTEP (either as a primary research tool, or as part of a suite of modeling and experimental techniques) industrial research will obtain new materials in a wide range of research disciplines which will then be used in, for example, new devices, new opto-electronic materials and possibly new medical treatments. Such research will also add to the basic fundamental understanding of materials at the electronic and atomic levels. All three host institutions already have well established outreach programmes; for example, summer schools for high-school students. The wide areas of application touched by this proposal will feedback into these presentations, and we can use our expertise to further inform and inspire young people in science.