Jacinto Sa: Solving chemical mechanisms with X-ray spectroscopy

As a scientist have been always fascinated with how chemical systems react and interact with the natural world. Spectroscopy is a great tool to look at systems in real-time and operation conditions. Hard X-ray photon-in photon-out spectroscopy offers great possibilities due to its chemical sensitivity and speciation as well as high penetration. In this webinar, I will talk about two chemical processes and the developments in X-ray spectroscopy that made the studies possible. My studies have been made possible with the development of the dispersive von Hamos-type spectrometer (1), which enabled us to perform high-resolution studies on real systems due to its simple and versatile geometry. The first case study is called atomic telemetry, a method that enables us to follow chemotherapy drugs action mechanism under physiological conditions. The methodology was validated with a known drug (cisplatin) but in this webinar, I will present the findings from a drug (Pt-103) with an unknown action mechanism (2). The second case relates to the understanding of plasmonic materials hot carrier formation, and their importance to solar applications. Using synchrotron radiation and HR-XAS we were able to demonstrate for the first time the formation of hot electrons (3). However, to address their dynamics one needed to develop a way to perform RIXS measurements at the XFEL with the shortest and most intense X-ray pulses. I will show how we can do that (4) and what we plan to do with this methodology.

References: (1 ) J. Szlachetko et al. Rev. Scie. Instrum. 2012, 83, 103105 https://doi.org/10.1063/1.4756691 (2 ) J. Czapla-Masztafiak et al. J. Phys. Chem. Lett. 2017, 8, 805-811 https://doi.org/10.1021/acs.jpclett.7b00070 (3) J. Sá, et al. Energy Scie. Technol. 2013, 6, 3584-3588 https://doi.org/10.1039/C3EE42731E (4) Y. Kayser et al. Nat. Commun. 2019, 10, 4761 https://doi.org/10.1038/s41467-019-12717-1