The 2022 Topical Call on Molecular Water Science
Addressing major societal challenges (such as climate change, clean energy and environment) is part of the Vision Statements of European XFEL and in line with major Strategic Goals of the European XFEL 2030+ Strategy. Thus, in early 2022, European XFEL launched a Call for Expressions of Interest in Molecular Water Science with the goal to attract new communities and to combine its unique X-ray infrastructure with the expertise of European and international partners in water related sciences. The call was prepared together with DESY’s Centre for Molecular Water Science (CMWS) and resulted in 25 proposals involving 209 scientists, 61 of them being first time proposers, with requests for all 6 European XFEL instruments. The proposals were peer-reviewed together with proposals submitted for other areas and the 7 top-ranked projects were accepted for beamtime in period 2023-I using reserved beamtime slots at the 6 instruments. One experiment was carried out in period 2023-II after resubmission.
The majority of the accepted projects focused on studying fast (fs-ps) equilibrium or non-equilibrium structural evolution of (undercooled) water and/or pathways towards the formation of ice nuclei or novel (glassy) ice phases upon fast cooling or fast compression. Two experiments either looked at how X-ray induced intermolecular dynamics evolves in the smallest H-bonded system, the water dimer (D2O), or how precursor hydrate structures form in (THF) doped water. The experiments' portfolio shows a certain emphasis towards addressing Fundamental Properties, Climate, Astro & Geo Sciences and Real-Time Chemical Dynamics. The impact for Energy Research/Technology and Molecular Life Sciences is however evident.
Common to all projects was the request for forefront experimental methods and techniques (XPCS, XCCA, COLTRIMS, RIXS and Pump-Probe) and sample environments (dDAC and liquid jets). Another common feature was the extensive use of large pixelated detectors such as the AGIPD and LPD producing massive amounts of data. The water hydrate experiment collected 1.13 PB of data. 5x108 2D diffraction pattern were collected at SPB/SFX. In many cases also new data analysis strategies (AI based/machine learning) are being developed and tested at newly taken data sets.
Areas of Molecular Water Research (adapted from CMWS White Paper DOI: 10.3204/PUBDB-2021-01859)
As of today (May 2024) data analysis is still ongoing on all executed experiments. However, first results are being reported from all experiments. These have been collected within a newly established monitoring process following the experiments from the campaign closely via interviews and videos during the experiment (reported here) and close interactions with the PI/MP in the data analysis phase including a small, on invitation-only, workshop. Each experiment will also be covered by an information leaflet containing, besides the interview, also a page describing the involved instrument and a contribution by the PI/Main proposer, describing the science content of the experiment and its outcome in more detail.
An open workshop on Molecular Water Science was held on January 23, 2024 in the framework of the 2024 Users Meeting and brought together more than 80 scientists. On that occasions, a second call on Molecular Water Science was announced with a deadline towards end of April 2024 and to be carried out in the first period of 2025 (2025-I). The scope of the call shall include work on water solutions, energy/water splitting, environmental and climate research. It shall involve a one-step application's process, a standard peer-review process with the help of international experts and a guaranteed beamtime slot per instrument if the proposal is ranked within the top 50% category.