Efficient global structure optimization in confined spaces: development and applications for design of advanced materials

• Applicant: Dr. Lukas Grajciar
• Subject Area: Theoretical Chemistry: Molecules, Materials, Surfaces ; Theoretical Chemistry: Electronic Structure, Dynamics, Simulation
• Term: from 2014 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 269386423

Nanoparticular systems in form of clusters and nanoparticles often exhibit unique chemical, electronic or optical properties. Global structure optimization algorithms employing quantum mechanical (QM) methods, in particular density functional theory, have proven essential in the structure determination of such systems. However, in order to realize the application potential of nanoparticular systems they have to be assembled into superstructures employing confining environments in form of an embedding matrix or capping ligands. The inclusion of confining effects within the framework of global structure optimization algorithms employing QM methods results in a significant increase of computational demands. Therefore, the aim of the project is to develop a tool for global structure optimization in confined spaces, GOCONS, which will allow locating of the most stable structures of nanoparticular systems confined in host materials in a computationally efficient way. This will be achieved combining genetic algorithm as the global structure optimization method with the hybrid quantum mechanics/molecular mechanics (QM/MM) scheme that limits the QM description only to the most relevant part of an extended system. In order to achieve the necessary performance of global structure optimizations at the QM/MM level the low-memory density fitting method developed recently by the applicant will be applied in DFT-based QM calculations. The application potential of the GOCONS tool will be demonstrated for structure determination of PbS quantum dots confined in the zeolite host with LTA topology. In addition, possible ways for fine-tuning of the properties and structure of the quantum dots, such as the type of charge neutralizing cations within the zeolite host will be investigated.

• DFG Programme: Research Grants