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Controlling the orientation of molecules inside liquid helium nanodroplets (DropletControl)
Date du début: 1 mai 2013, Date de fin: 30 avr. 2018 PROJET  TERMINÉ 

In this project I will develop and exploit experimental methods, based on short and intense laser pulses, to control the spatial orientation of molecules dissolved in liquid helium nanodroplets. This idea is, so far, completely unexplored but it has the potential to open a multitude of new opportunities in physics and chemistry. The main objectives are:1) Complete control and real time monitoring of molecular rotation inside liquid helium droplets, exploring superfluidity of the droplets, the possible formation of quantum vortices, and rotational dephasing due to interaction of the dissolved molecules with the He solvent.2) Ultrafast imaging of molecules undergoing chemical reaction dynamics inside liquid helium droplets, exploring rapid energy dissipation from reacting molecules to the helium solvent, transition between mirror forms of chiral molecules, strong laser field processes in He-solvated molecules, and structure determination of non crystalizable proteins by electron or x-ray diffraction.I will achieve the objectives by combining liquid helium droplet technology, ultrafast laser pulse methods and advanced electron and ion imaging detection. The experiments will both rely on existing apparatus in my laboratories and on new vacuum and laser equipment to be set up during the project.The ability to control how molecules are turned in space is of fundamental importance because interactions of molecules with other molecules, atoms or radiation depend on their spatial orientation. For isolated molecules in the gas phase laser based methods, developed over the past 12 years, now enable very refined and precise control over the spatial orientation of molecules. By contrast, orientational control of molecules in solution has not been demonstrated despite the potential of being able to do so is enormous, notably because most chemistry occurs in a solvent rather than in a gas of isolated molecules.