Decahedral Nanoparticles Research Articles

Structural Instabilities in Passivated Gold Nanoclusters Induced by Electron Irradiation

In the new nanotechnology devices design, the stability of the systems is very important, in the present work we report evidences of internal and external changes of nanoparticles passivated by thiol molecules when they are irradiated under a high flux of an electron beam in the transmission electron microscope. High Resolution images were digitized and processed in order to identify the contrast changes produced by the atomic inside the nanoparticles. Fcc and decahedral nanoparticles cases are shown. Molecular dynamics calculations are also included in order to compare the experimental evidences with the cluster conditions of stabilities. Both theoretical and experimental results imply the occurrence of atomic and twining movements, and indicate that the n-alkyl thiol molecules prevent atomic movement and changes on the particle structure are not observed.

Disclination in an elastic sphere

Abstract The boundary problem for a wedge disclination axially arranged in an isotropic sphere having a free surface has been solved exactly. This solution is applicable for the analysis of the stability of pentagonal symmetry in decahedral and icosahedral nanoparticles. It is shown that the character of elastic fields in the sphere is intermediate between those for plain-stressed and plain-strained states, and this proves the hypothesis proposed in the paper of Dundurs, Marks and Ajayan (1988).