Large scale electronic structure calculations in the study of the condensed phase

Abstract

We consider the role that large-scale electronic structure computations can now play in the modelling of the condensed phase. To structure our analysis, we consider four distict ways in which today's scientific targets can be re-scoped to take advantage of advances in computing resources: 1. time to solution-performing the same calculation, with delivery of the simulation in shorter elapsed time; 2. Size-applying today's methods to a more extensive problem; 3. Accuracy-replacing current physical models with more accurate ones; 4. Sampling-simultaneously studying more chemical or conformational states. Each of these offer some scientific rewards, but all present thenological challenges and it is likely that a mixture of approaches will be needed to make the best use of capability computing. We discuss some aspects of our work in each of these areas, including replicated and distributed data parallel implementations of GAMESS-UK, and approaches incorporating multi-level parallelism. Examples of the latter include pathway optimization using replica methods and task farming approaches to global optimization problems. We consider a typical application of GAMESS-UK to heterogeneous catalysis, and the role that large-scale DFT vibrational frequency calculations have played in the study of partial oxidation catalysts incorporating supported VOx species.