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.
RECRUTEMENT ACCES DIRECT
Le département de physique
Fête de la Science 2018 