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MO: Fachverband Molekülphysik

MO 23: Molecular Theory

MO 23.1: Hauptvortrag

Freitag, 15. März 2019, 10:30–11:00, S HS 001 Biologie

Efficient charge transfer by electron transfer mediated decay mechanism — •Kirill Gokhberg — Theoretical Chemistry, Heidelberg University, Heidelberg, Germany

Charge transfer between atoms and molecules is enabled by several mechanisms. It can proceed due to the coupling to the vibrational degrees of freedom, or via photon emission, in which case it is typically slow. In this talk I will present electron transfer mediated decay (ETMD), a charge transfer process enabled by interatomic electron correlation, which is usually fast. In ETMD charge transfer takes place between singly or multiply ionised atoms embedded in chemical environment and their neighbours, such that the transfer of the electron to the ion is accompanied by the emission of a second electron from the environment to the continuum. Whenever energetically allowed the process is highly efficient. Calculated ETMD lifetimes in rare gas clusters are less than a few picoseconds, while for solvated positive ions they can be as short as few tens of femtoseconds. The theoretical findings were confirmed by recent experiments, which showed the existence of ETMD in salt solutions and mixed rare gas clusters. Importantly, it was demonstrated that this process plays a crucial role in redistributing throughout a larger chemical system a localised positive charge produced by the action of ionising radiation. ETMD was also shown in theory and experimentally to furnish an efficient indirect pathway for producing cold doubly ionised species embedded in He nanodroplets by ionising the host He matrix.