Structural Stability and Thermodynamic Properties of (Y2O3)n(n=1-15) Clusters Based on Density Functional Theory

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.