Vapor
Condensed and Supercooled Glassy Nanoclusters
Weikai Qi
Richard K. Bowles
10.1021/acsnano.5b07391.s001
https://acs.figshare.com/articles/journal_contribution/Vapor_Condensed_and_Supercooled_Glassy_Nanoclusters/2299672
We use molecular simulation to study
the structural and dynamic
properties of glassy nanoclusters formed both through the direct condensation
of the vapor below the glass transition temperature, without the presence
of a substrate, and via the slow supercooling of unsupported liquid
nanodroplets. An analysis of local structure using Voronoi polyhedra
shows that the energetic stability of the clusters is characterized
by a large, increasing fraction of bicapped square antiprism motifs.
We also show that nanoclusters with similar inherent structure energies
are structurally similar, independent of their history, which suggests
the supercooled clusters access the same low energy regions of the
potential energy landscape as the vapor condensed clusters despite
their different methods of formation. By measuring the intermediate
scattering function at different radii from the cluster center, we
find that the relaxation dynamics of the clusters are inhomogeneous,
with the core becoming glassy above the glass transition temperature
while the surface remains mobile at low temperatures. This helps the
clusters sample the highly stable, low energy structures on the potential
energy surface. Our work suggests the nanocluster systems are structurally
more stable than the ultrastable glassy thin films, formed through
vapor deposition onto a cold substrate, but the nanoclusters do not
exhibit the superheating effects characteristic of the ultrastable
glass states.
2016-02-11 00:00:00
energy regions
ultrastable glass states
bicapped square antiprism motifs
superheating effects
glass transition temperature
cluster center
vapor deposition
energy landscape
supercooled clusters access
clusters sample
Voronoi polyhedra
energy surface
Supercooled Glassy Nanoclusters
structure energies
relaxation dynamics
nanocluster systems
Vapor Condensed
energy structures