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Levi Keller from the CEST group is a recipient of a recently announced Finnish Cultural Foundation Award. His doctoral studies harness the increasingly important intersection of computational science and spectroscopy studies to relate experiment to theory. These predictions provide fundamental insight into the structural, chemical and electronic properties of materials.

Spectroscopic experiments, such as x-ray photoelectron spectroscopy, allow the observation of addition and removal energies of electrons in materials. Often these observed spectra contain many partially overlapping features and complex satellite structures, and the ability to calculate electron removal and addition energies with numerical accuracy within experimental resolution is critical to their interpretation. The GW approximation to many-body perturbation theory is a proven method to compute these spectral features with high accuracy, but is limited by its high computational expense and poor scaling with system size to systems of at most several hundred atoms. This limitation severely restricts its application, excluding a wide range of real world systems, such as ionic liquids, molecules adsorbed on a surface, or molecular crystals. Embedding approaches circumvent these limitations by combining a less computationally cumbersome description of the key effects of a large and complex environment with a highly accurate description of a focal region in the material of interest.

This grant will be utilized to develop an embedding scheme for the GW approximation. This method will extend the highly accurate quantitative interpretative capability already attained for gas-phase molecules to entirely new classes of extended systems.

Congratulations!