<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "Neutralization and relaxation of cations in an environment driven by interatomic decay processes"^^ . "Non-local electronic decay mechanisms constitute important pathways for the relaxation of cations produced by the action of ionizing radiation in van-der-Waals or hydrogen\r\nbonded chemical environment. Electronically excited cations may undergo the ultrafast\r\nInteratomic Coulombic Decay or ICD process, whereby the excess electronic energy is\r\ntransferred to the environment and used to ionize it. It has been extensively studied by\r\ncomputational and experimental techniques during the last two decades and shown to\r\noperate in a variety of systems from rare gas dimers to large biomolecules. In this thesis\r\nwe investigate using ab initio methods the Electron Transfer Mediated Decay or ETMD\r\nprocess which is responsible for the charge redistribution in environment, whenever\r\natomic cations with a low excess energy and high electron affinity are produced. In\r\nETMD electron transfer to the cation leads to the emission of an electron from the\r\nneighboring species. The net result is partial neutralization of the cation and the increase\r\nof the charge of the environment by two.\r\n\r\nThe light rare gas atoms He and Ne have a high ionization potential and, in the\r\npresence of a suitable neighbor are likely to undergo ETMD when they are singly ionized,\r\ne.g. by photoionization. In particular, we showed that a HeMg cluster efficiently\r\ndecays by ETMD whenever He is photoionized and a ground state He+ ion is produced.\r\nThe joint process of photoionization and ETMD corresponds to a one-photon double\r\nionization of Mg. Remarkably, we found that the cross section of this process is three\r\norders of magnitude higher than the cross section of the atomic one-photon double\r\nionization, which demonstrates the prominent role of the neighboring He species in the\r\ndouble ionization. This mechanism of the ETMD driven one-photon double ionization\r\nwas recently demonstrated experimentally in doped He nanodroplets and is proposed as\r\na method for the experimental production of cold molecular dications.\r\n\r\nMultiply charged rare gas cations have higher electron affinities and undergo ETMD\r\nwith a larger variety of neighboring atoms or molecules. Such cations are naturally produced by the Auger decay following core ionization of rare gases in the X-Ray absorption.\r\nThe ETMD process reduces their positive charge by one, i.e. leads to their partial neutralization and serves as a purely electronic alternative to neutralization mechanisms\r\ndriven by the movement of the nuclei. Our calculations show that in small Ne2+Xe\r\nand Ne2+Kr2 clusters the ETMD process takes place on a picosecond timescale. The\r\nETMD in these systems is accompanied by nuclear dynamics which in turn enhance the\r\nrate of the electronic decay. We show that for such systems ETMD is an important\r\nmechanism responsible for the fast redistribution of the localized charge produced in\r\nthe Auger decay process.\r\n\r\nWe also demonstrated that multiply charged hydrated metal cations are likely to decay\r\nvia complicated cascades comprising both ETMD and ICD steps. Our calculations\r\nin the Mg2+(H2O)6 microsolvated cluster showed that such a cascade proceeds on a\r\ntimescale of few hundreds of femtoseconds and leads to a massive degradation of the\r\nimetal’s solvation shell through its multiple ionization and emission of slow electrons.\r\nRepulsive nuclear dynamics at later stages of the cascade, which were not taken into\r\naccount explicitly, are expected to considerably reduce its duration. We expect that\r\nstudying interatomic decay cascades of metal cations is important for understanding\r\nmechanisms of the damage caused by X-Rays to metal containing biomolecules such as\r\nDNA, metalloproteins etc. For the latter of particular importance is the knowledge of\r\nthe duration of different interatomic decay steps, since it determines the timescale at\r\nwhich proteins become damaged by X-Rays and beyond which their structure becomes\r\ncompromised.\r\n\r\nThese considerations led us to investigate the dependence of ICD lifetimes on atomic\r\ncharge in excited microhydrated Na2+ and Mg3+ cations. Our ab initio results reproduce\r\nwithin the numerical error the experimental ICD lifetimes of the respective ions in\r\naqueous solutions. We show that the microsolvated Mg3+ cations decay faster than\r\nthe Na2+ ones, in accordance with experiments on aqueous solutions. The detailed\r\nanalysis reveals that at characteristic metal-water separations the polarization of the\r\nwater neighbor enhances ICD the stronger the higher the charge of the metal is. This,\r\ntogether with the shorter Mg-water equilibrium distances, leads to the observed ordering\r\nof the ICD rates. We also showed that polarizing the neighbors causes sub-linear growth\r\nof ICD rates with the number of water molecules in the first solvation shell. This\r\ninvestigation of ICD in microsolvated metal cations demonstrated the prominent role\r\nthe cation’s charge and the consequent polarization of the medium have on the decay\r\nrate. It also leads to a reasonable expectation that even faster, sub-femtosecond decay\r\nlifetimes might be achieved for highly charged solvated metals ions."^^ . "2017" . . . . . . . "Vasili"^^ . "Stumpf"^^ . "Vasili Stumpf"^^ . . . . . . "Neutralization and relaxation of cations in an environment driven by interatomic decay processes (PDF)"^^ . . . "Dissertation.pdf"^^ . . . "Neutralization and relaxation of cations in an environment driven by interatomic decay processes (Other)"^^ . . . . . . "lightbox.jpg"^^ . . . "Neutralization and relaxation of cations in an environment driven by interatomic decay processes (Other)"^^ . . . . . . "preview.jpg"^^ . . . "Neutralization and relaxation of cations in an environment driven by interatomic decay processes (Other)"^^ . . . . . . "medium.jpg"^^ . . . "Neutralization and relaxation of cations in an environment driven by interatomic decay processes (Other)"^^ . . . . . . "small.jpg"^^ . . . "Neutralization and relaxation of cations in an environment driven by interatomic decay processes (Other)"^^ . . . . . . "indexcodes.txt"^^ . . "HTML Summary of #22482 \n\nNeutralization and relaxation of cations in an environment driven by interatomic decay processes\n\n" . "text/html" . . . "000 Allgemeines, Wissenschaft, Informatik"@de . "000 Generalities, Science"@en . . . "500 Naturwissenschaften und Mathematik"@de . "500 Natural sciences and mathematics"@en . . . "530 Physik"@de . "530 Physics"@en . . . "540 Chemie"@de . "540 Chemistry and allied sciences"@en . .