Section: Application Domains

Atomic Simulation Environment

Embedding methods have been proven to be a very useful tool in Quantum chemistry. They have successfully applied to determine structures, energetics and reaction pathways in biochemistry and heterogeneous catalysis. The mechanical embedding scheme has been implemented in the Atomic Simulation Environment program (ASE) by the Chemistry Laboratory of the ENS. It combines two different quantum chemistry methods (Low Level (LL) and High Level (HL)) to form the hybrid HL:LL potential energy surface. The implementation can be used with all calculator classes implemented in ASE (e.g VASP, TURBOMOLE) as as HL- or LL-method. In order to calculate the hybrid energy, three separate calculations are necessary which can have totally different computational demands (e.g RAM, number of processors). In order to perform such calculations efficiently, our hybrid implementation is going to be coupled with the DIET middleware within the CADENCED project. This middleware program distributes the needed calculations over different platforms in order to maximize the overall performance, which allows us to combine molecular mechanic calculations for hundred thousands of atoms (running efficiently on several thousand processors) with ab initio calculations for dozens of atoms (running efficiently on a few tens processors) with high performance. This work is in progress in relationship with the Chemistry Laboratory of the ENS de Lyon.