1. What is e-Science? e-Science refers to large scale science that will increasingly be carried out through distributed global collaborations enabled by the Internet. will require access to very large data collections large scale computing resources high performance visualisation back to the individual user scientists Besides information stored in Web pages, scientists will need easy access to remote computing resources and to information stored in dedicated databases. Acid Sites in Zeolites Determine the extra-framework cation position within the zeolite framework. Explore which proton sites are involved in catalysis and then characterise the active sites. Produce a database with structural models and associated vibrational modes for different Si/Al ratios. Improve understanding of the role of the Si/Al ratio in zeolite chemistry. The aim of this project is to apply e-Science and Grid technologies to the area of polymorph prediction. A method of predicting which crystal structure a given organic molecule will adopt is important in a number of areas, as changes in polymorphic form can affect properties such as the colour of pigments, detonation stability of energetic materials and the properties of pharmaceutical drugs. As an example, we apply the polymorph prediction methodology to find possible polymorphs of parabanic acid. Prediction of the possible polymorphism involves the three stages. Parabanic acid Polymorphism and Properties of Parabanic Acid MOLPAK Generation of crystal packings into 29 packing types Optimisation of density of unit cell DMAREL Lattice energy optimisation Geometrical data : Unit cell volume, density Energetical data : Lattice energy  Restricted number of structures selected Crystal structures and properties stored in Database N ~ 1500 Optimised Molecular Structure Morphology N ~ 100 Plot of lattice energy against cell volume per molecule for all the minima found in the MOLPAK search We next calculate the growth morphology (attachment energy of the observed faces) of the observed and predicted polymorphs and use this as an aid in judging whether a certain polymorph is likely to exist. From the attachment energy values we also calculate the growth volume. This is the volume within the Wulff shape and is calculated by numerical integration. Growth volume and attachment energy for polymorphs of parabanic acid From this, we see that the observed polymorph grows relatively fast, although other polymorphs are possible. Predicted morphology of the observed polymorph of parabanic acid At the end of this process, a large number of hypothetical structures are obtained. Those within 2-6 kJ mol -1 of the global minimum could be considered as possible polymorphs as they have reasonable mechanical properties and relative growth rates. e-Science Technologies in the Simulation of Complex Materials S. A. French, D. S. Coombes, C. R. A. Catlow – RI B. Butchart, W. Emmerich – UCL CS H. Nowell, S. L. Price – UCL Chem L. Blanshard, R. Tyer, K. Kleese - CLRC Combinatorial Computational Catalysis Polymorphism A combined Monte Carlo and energy minimisation approach has been developed to model zeolitic materials with low and medium Si/Al ratios. Firstly Al is inserted into a siliceous unit cell and then a charge compensating cation, such as Na, is added between two of the oxygens coordinated to Al. The zeolite Mordenite, which has a 1 dimensional channel system, has been studied with a simulation cell containing two unit cells, which means 296 atoms, with 96 Si centres (referred to as T sites). We have made extensive use of Condor pools (for example UCL – 950 nodes in teaching pools). 48 cpu-years of previously unused compute resource have been utilised in this study. We have run 50,000 calculations each with 488 particles per simulation box, which means a grand total of 24,000,000 particles have been included in our simulations to date. When we have confirmed the lowest energy positions of Al the cation is exchanged for a proton and again energy minimised. This method along with the exploitation of low specification computational resources will allow us to construct realistic models of low and medium Si/Al zeolites. Such structures can be used for further simulations and aid the interpretation of experimental data. It can be seen in both graphs that there are two distinct regions, -12079eV to -12076eV and -12075eV to -12073eV. From the upper graph there is no obvious correlation between total energy and cell volume. However, when 10,000 structures are considered it is clear that the most stable structures correspond to cation placements that do not cause the cell to expand. This requires that the cations sit in the large channel, shown in the picture below left. 0 100 10000 0