Impurity effects on phase change in Lennard-Jones atomic clusters

Abstract

In this work, we would like to explore the possibility of studying phase change behaviour in pure Lennard-Jones clusters as well as the effect of introducing a heteroatom. The system studied are ${\textrm{Ar}}_{10}$, ${\textrm{Xe}}_{10}$ and ${\textrm{Ar}}_{10-1}{\textrm{Xe}}_1$ as well as ${\textrm{Ar}}_{10-9}{\textrm{Xe}}_{9}$. The phase change is followed by the temperature variation in classical configuration heat capacity. As the heat capacity is calculated by evaluating the variance in the energy of the isomers possible, an important aspect is to sample the Lennard-Jones surface effectively and pick out as many isomers which are possible for this system. The sampling at various temperatures has been done using the replica exchange Monte Carlo or Parallel tempering procedure. The main focus of the present work is to see how the phase change behaviour is affected on going from the pure Lennard-Jones systems to the once possessing dopants. To further aid in the understanding bond length fluctuation parameter has also been calculated for all the systems with changing temperature along with the classical configuration.

Graphical abstract

Synopsis: The phase change behavior of pure Lennard-Jones clusters and the effect of introducing a heteroatom was studied using replica exchange Monte Carlo or parallel tempering techniques and examining the classical configuration heat capacity and bond length fluctuation parameter. The systems studied were Ar₁₀ , Xe₁₀ and Ar₁₀₋₁ Xe₁ as well as Ar₁₀₋₉ Xe₉.