Theoretical investigation of thermodynamic balance between cluster isomers and statistical model for predicting isomerization rate

By molecular dynamics simulations and free energy calculations based on Monte Carlo method, the detailed balance between Pt cluster isomers was investigated. For clusters of n<=50, stationary equilibrium is achieved in 100 ns in the canonical ensemble, while longer time is needed for n>50. Then, a statistical mechanical model was built to evaluate unimolecular isomerization rate and simplify the prediction of isomer formation probability. This model is simpler than transition state theory and can be easily applied on ab initio calculations to predict the lifetime of nanostructures.