"PhD Mid-term Seminar Series: Modelling Radiolysis in Liquid Phase Electron Microscopy (LP-EM): from fundamentals to applicative simulations"
Who: Giuseppe De Salvo, Pre-doctoral Researcher, Electron Microscopy, CIC nanoGUNE
Place: nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian
Date: Monday, 12 September 2022, 11:00
Modelling Radiolysis in Liquid Phase Electron Microscopy (LP-EM): from fundamentals to applicative simulations
Giuseppe De Salvo
Pre-doctoral Researcher, Electron Microscopy, CIC nanoGUNE
Observing chemical reactions in their native liquid environment has always been the desire of scientists in order to understand the nanoscale world. This desire has led to the invention of liquid-phase electron microscopy1 (LP-EM) as a visualisation technique: an aqueous sample is enclosed in liquid cells about few hundreds of nanometers thick and irradiated with a high-energy electron beam, to obtain real-time videos of the evolution of the chemical-physical processes. However, there are still many problems that limit the capabilities of the technique; above all, the energy transferred from the high-energy electrons of the beam to the aqueous medium, resulting from inelastic scattering. A cascade of reactions is triggered, in which highly reactive species are created (radiolytic) and diffuse in the liquid phase. Such species are recognised to interfere with the reactions observed by LP-TEM2. As there is a limited number of methods to monitor chemical environment in sub-micrometer confined space of the cell, simulation methods play a key role in predicting the chemistry inside the irradiated liquid cell. Herein, we show an overview of models intended to qualitatively and quantitatively describe the radiolysis in his fundamentals aspects and more applicative scenarios. A model vastly used3 in literature is questioned in the assumptions; and strategies for fighting or control the effects of radiolysis inside the liquid cell are predicted and commented. This methodologies lead to promising results for the optimisation of imaging conditions under the microscope.
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