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Title: Generalized Lorenz-Mie theories and mechanical effects of laser light, a celebration of Arthur Ashkinâ€™spioneering work in optical levitation and manipulation.
G. Gouesbet has been working in light scattering, modeling of two-phase flows, non linear dynamics and chaos theory., and is the promoter of the well-known generalized Lorenz-Mie theory. He authored about 350 papers in journals and as a whole about 550 papers in journals and proceedings. His citation count in Google scholar is about 13 000 with a h-index of 58. He has been serving in numerous committees and is a honorary editor of Journal of Quantitative Spectroscopy and Radiative Transfer.
The generalized Lorenz-Mie theory (GLMT, more generally GLMTs)  has been initially developed to address issues in optical particle characterization, more particularly in optical particle sizing, in order to simultaneously measure velocities and sizes of individual particles embedded in flows, with applications to spray combustion or plasma spraying, among others. This line of research, however, had two opportunities to meet another line of research, namely the one of Arthur Ashkin dealing with optical levitation, trapping and manipulation of macroscopic particles (such as droplets or beads), and who won a Nobel prize in physics last year. The first opportunity has been that GLMT (more generally GLMTs) is able to deal with mechanical effects of light whatever the size of particles and then indeed bridged the gap between the Rayleigh and ray optics regimes to which the theoretical part of the work of Arthur Ashkin was limited. The second opportunity has been that optical levitation experiments promoted by Arthur Ashkin have been used to experimentally test the validity of the GLMT. In this talk, as a celebration of Arthur Ashlin’s pioneering work concerning the mechanical effects of laser light, I shall offer a review and overview devoted to GLMTs and mechanical effects of laser light, both in Rouen where the GLMT has been built, and all over the world.
Title: AI in Physics
Hakima Mokrane is a researcher in laboratory astrophysics & astrochemistry and now a researcher scientist in machine learning, she designs algorithms for solving AI problems. She graduated from Orsay university with a master (joint Honours) in Physics and Chemistry, before completing her PhD (in molecular physics & laboratory astrophysics) at Paris Observatory and Cergy University. Her interests span "all things ice and molecules", looking at how solid-state materials play a role in the processes of star and planet formation. She combines laboratory experiments with major facilities use, to understand the roll of ice in interstellar chemistry and planet forming collisions and exploit molecular dynamics simulations to understand the physical chemical properties of ice in space and now she is designing and building algorithms to solve AI problems and is interested in the problems of machine learning, deep learning and AI.
200 different species detected up today in the interstellar and circumstellar media have also been identified in icy environments. The fact that, for most of the species observed so far in the ISM, the most abundant isomer of a given generic chemical formula is the most stable one (MEP) suffers very few exceptions. Two couples of isomers, CH3COOH/HCOOCH3 and CH3CH2OH/CH3OCH3 whose formation is thought to occur on the icy mantles of interstellar grains. Here, we report a coherent and concerted theoretical/experimental study of the adsorption energies of: AA/ MF and EtOH / DME on the surface of water ice at low temperature. For each pair of isomers, theory and experiments both agree that it is the most stable isomer (AA or EtOH) that interacts more efficiently with the water ice than the higher energy isomer (MF or DME). This differential adsorption shows clearly in the different desorption temperatures of the isomers. It is not related to their intrinsic stability but linked to the fact that both AA and EtOH make more and stronger hydrogen bonds with the ice surface.The formation of water molecules from the reaction between O3 and D-atoms is studied experimentally for the first time. Ozone is deposited on non-porous amorphous solid water ice, and D-atoms are then sent onto the sample held at 10 K. HDO molecules are detected during the desorption of the whole substrate where isotope mixing takes place, indicating that water synthesis has occurred. The efficiency of water formation via hydrogenation of ozone is of the same order of magnitude as that found for reactions involving O-atoms or O2 molecules and exhibits no apparent activation barrier. These experiments validate the assumption made by models using ozone as one of the precursors of water formation via solid-state chemistry on interstellar dust grains.Here we applied machine learning and AI to build and improve moleculars reactions.