When 9:00 AM - 10:30 AM Nov 30, 2007
Where 1670 CSE
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Emilio Artacho, Cambridge University

Calculating Radiation Damage by Ions in Insulating Materials: the Onset of Non-Adiabatic Effects

Within an effort to predict the fate of nuclear waste diluted in suitable ceramic materials (synthetic rocks to be buried), I am interested in simulating the damage produced in insulators by radioactive decay processes. One of the most damaging processes for the host material is the formation of amorphisation cascades by the recoil of heavy nuclei after alpha decay processes.
Simulations of these processes to date assume adiabaticity in the electron dynamics. Is this justified? Do these recoil events produce short lived hot liquids, or are electron excitations playing a role?
I will focus on simulating electronic excitation by "slow" ions in LiF, a paradigmatic insulator for the study of ion stopping by electrons, and explore the electronic stopping power (rate of energy uptake
by electrons) as a function of projectile velocity. Results will be presented for first-principles simulations of that rate based on time-dependent density functional theory, especially focusing on
the controversial velocity threshold.

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