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Study of solvated molecular ion stability in the gas-phase : cooling and irradiation

Abstract : Radiation can damage our biological environment, but it can also be beneficial under certain controlled conditions. Initial action at microscopic scale consists of electronic excitation in molecules. The redistribution of this excitation energy to the environment is the primary process to be understood to describe the radiation effect on biomolecular system. Isolated molecular clusters in gas-phase are a promising model system to study the molecular interaction under radiation.The first part of this work describes the construction and the validation of a beamline which can produce bunches of cold molecular cluster ions to be injected in the RIKEN cryogenic electrostatic (RICE} storage ring. The beamline is composed of an electrospray ion source, a quadrupole mass filter, ion guides and an acceleration tube; with the main part being a cryogenic ion trap cool down to SK. The cold ion bunches, in which the ions have been mass selected and accelerated to 20keV, was probed with a laser. The beamline was successfully taken into operation and a measurement of the methylene blue action spectrum in gas-phase was carried out. The second part of this work rely on experiment realized with the dispositif d'irradiation d'agrégats moléculaires (DIAM-IPNL}. The COINTOF-VMI method allows the measurement of the velocity distributions of evaporated molecules from a cluster after high velocity collisions with an argon atom. The velocity distribution measured for mixed clusters protonated pyridine and water has two components: a low velocity part which corresponds to the evaporation of a water molecule after energy redistribution in the cluster, and a high velocity part in which the molecule is evaporated before total energy redistribution. Comparison with the distribution calculated by statistic molecular dynamic simulation shows that the low velocity part can be interpreted as the contribution of two possible excitations induced by collision: excitation on protonated pyridine and excitation on a water molecule
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https://tel.archives-ouvertes.fr/tel-01710261
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Submitted on : Thursday, February 15, 2018 - 5:17:06 PM
Last modification on : Tuesday, November 19, 2019 - 2:44:46 AM
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  • HAL Id : tel-01710261, version 1

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Paul Bertier. Study of solvated molecular ion stability in the gas-phase : cooling and irradiation. Nuclear Experiment [nucl-ex]. Université de Lyon, 2017. English. ⟨NNT : 2017LYSE1207⟩. ⟨tel-01710261⟩

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