Analysis of the dynamical and thermal responses of the elemental subsystems of a nanoalloy to the change of its energy

We present results of a classical molecular dynamics study of a 13-atom bimetallic Ni/Al cluster and analyze the peculiarities of its dynamical/thermal behavior using novel subsystems-level descriptors. Specifically, we introduce the notions of subsystems temperature, specific heat and index of anharmonicity and use them to analyze and characterize the differences in the dynamical/thermal responses of the Ni and Al subsystem to the change of energy (or temperature) of the cluster. The energy range covered is broad enough to encompass all the stages of the solidlike-to-liquidlike transition in the cluster. The subsystems-specific responses as a function of the cluster energy are then further analyzed as a function of the cluster composition (i.e. the number of Ni and Al atoms in it). The dynamical/thermal behavior of the pure Ni and Al 13-mers is also examined and is used as a basis for comparisons and evaluations.