Nucleation and growth at the nanoscale from transition pathways to reaction coordinates
Christoph Dellago (University of Vienna)

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Salle E244 - 24, rue Lhomond - 13h30

Jeudi 29 novembre

Under suitable conditions, first order phase transitions such as the freezing of a
liquid or the structural transformation of a solid occur via a nucleation and growth
mechanism, in which a nucleus of the stable phase is formed in the metastable
phase. For systems with sizes in the nanometer regime, the nucleation mechanism
and its kinetics are strongly affected by finite size effects. I will address this issue
using melting/freezing of gold nanoparticles and the Wurtzite-to-rocksalt transition
in CdSe nanocrystals as illustrative examples. Based on the results of transition
path sampling simulations, I provide a picture of the transition mechanism paying
particular attention to the structure of the critical nuclei. The role of the reaction
coordinate in the investigation of the transition mechanism is discussed.

Salle E244 - 24, rue Lhomond - 13h30