X-ray spectroscopic techniques, such as X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS), as well as different related techniques, have been instrumental in improving our understanding of the structure of complex materials. However, direct interpretation of experimental X-ray spectra is often hindered by overlapping signatures, e.g., two different atomic environments can contribute in the same region of a material’s spectrum, making it impossible to tell them apart. At the same time, experimentalists often rely on simplified theoretical references to interpret their spectra. For these reasons, simulations have always had an important role in interpretation of X-ray spectra since electronic-structure-based computations of core-level excitation energies became practical a couple of decades ago. Still, many challenges remain regarding the accuracy and cost of these computations, and how to reliably combine them with experiment. The field has seen rapid growth and development in recent years, due to fundamental and methodological development (e.g., the development of low-scaling algorithms for core-level spectroscopy) as well as the introduction of machine-learning techniques which are opening up avenues that were not previously obvious, both in terms of speeding up the computational predictions and integrating simulations and experiments.

This workshop aims to get the community of computational X-ray spectroscopy together, and discuss recent advances, outstanding challenges, and the directions in which the field will be developing in the near and medium future. In particular, the workshop will cover advances in 1) highly accurate electronic structure techniques, 2) methodologies for high-throughput spectra generation and materials screening, 3) machine learning to speed up X-ray spectra predictions, 4) machine learning to aid in the interpretation of experimental spectra, 5) structure inference from spectra, 6) novel techniques combining experimental and simulated spectra, 7) applications to specific materials and molecules.

While the event is focused on computational approaches, one of the aspects we want to highlight are the developments combining experiment and simulation, and we want to hear from experimentalists what are the outstanding challenges and how they understand the role of computations in aiding in the interpretation of experimental results. For this reason we have included experimental experts in the roster of invited speakers below.

Annika Bande (HZ Berlin, Germany)
Maria Chan (Argonne National Lab, US)
Dorothea Golze (TU Dresden, Germany)
Deyu Lu (Brookhaven National Lab, US)
Reinhard Maurer (University of Warwick, UK)
Mounir Mensi (EPFL, Switzerland)
Robert Palgrave (UCL, UK; TBC)
Paavo Penttilä (Aalto University, Finland)
Anna Regoutz (UCL, UK)
Sami Sainio (Aalto/SLAC)

The conference will take place in the main campus of Aalto University, in the Helsinki metropolitan area. The number of participation slots in this conference is limited. If you want to participate, please apply through the conference's website: https://ocamm.fi/event/recent-advances-in-computer-aided-x-ray-spectroscopy (all applications will be reviewed).

We are looking forward to a stimulating conference in Finland this Summer.

The scientific organizing committee:
Miguel Caro, Patrick Rinke and Tigany Zarrouk (Aalto University)