Structural Stability and Thermodynamic Properties of (Y2O3)n(n=1-15)
Clusters Based on Density Functional Theory
Abstract
The initial configuration of Yttrium oxide clusters (Y2O3)n(n=1-15) was
creatively constructed by combining artificial bee colony algorithm with
density functional theory. The structures of large and medium-sized
yttrium oxide clusters with molecular number greater than 10 were
established for the first time, and many new structures that are
different from existing research have been obtained. The average binding
energy, second-order difference energy, HOMO-LUMO gap, density of states
and other properties of the clusters were analyzed. The thermodynamic
properties and behavior of nano yttrium oxide clusters at different
temperatures and sizes were discussed. Studies have shown that for
small-sized clusters, the atomic stacking structure is cage-like, while
for medium-sized and large-sized clusters, the composite trapezoidal
structure and ellipsoid-like structure are more stable. The nanoclusters
tend to be stable as a whole, and the relative stability of the cluster
structure is higher when n = 2,4,7,9. The effect of yttrium oxygen
atomic orbital on bonding is analyzed. The heat capacity (Cp), enthalpy
change (H) and entropy (S) of (Y2O3)n (n=1-15) clusters increase with
the increase of temperature (T), and the vibration free energy (Gv)
decreases with the increase of T. The stability of the clusters changes
in the temperature range of 300K-500K.