Structural motifs and stability of small argon–nitrogen clusters

Abstract

The molecular dynamics (MD) simulation method is used to study Arm(N2)n clusters. Using realistic pair potentials for the argon–argon, nitrogen–nitrogen, and argon–nitrogen interactions, the structures and thermodynamics of these clusters are investigated. The initial focus of the study is the series of thirteen particle clusters of Arm(N2)13−m (0⩽m⩽13). These icosahedral argon–nitrogen clusters display systematic changes in energetics when argon is substituted by nitrogen in the central position. The relative stability of argon-centered clusters over nitrogen-centered clusters is further investigated by defining and calculating a “species-centric” order parameter which can be monitored during a MD simulation. These results are interpreted in terms of frustration effects due to anisotropy in the N2–N2 and N2–Ar potentials. The consequences of these observations for cluster stability and for dynamical behavior, such as melting and evaporation, are investigated. The dynamical studies of larger clusters reveal that the mixed clusters evolve towards a structure with an argon core coated by a nitrogen shell.

Direct FTIR high resolution probe of small and medium size Arn(CO2)m van der Waals complexes formed in a slit supersonic expansion

“…In both studies, the use of a gas mixture was proven to notably favor co-condensation of the expanding gases. Recent dynamical studies performed on mixed nitrogen-argon clusters [34,35] reveals that the more condensable argon forms a core of the mixed cluster while nitrogen forms an outer shell. In our case, the carbon dioxide gas has a much higher boiling temperature than argon; it is likely therefore to expect the central CO 2 embryo to be surrounded by a shell of argon atoms.…”

Interface identification by non-local autoionization transitions

“…Determining the composition of these clusters is intricate, and usually requires molecular dynamics simulations for the given expansion parameters. 5,8 In our work, we will demonstrate the appearance of an ICD signal due to the transition (Ne 2s…”

“…Simulated results show far more detail than currently is experimentally accessible. 7,8 In this article we introduce a method that directly identifies the two atomic or molecular species forming an interface in a weakly bonded complex. As an example we use van der Waals clusters of Ar, which are partially covered by a single layer of Ne atoms.…”

The study of dynamics and phase transitions of small Ag/Pd motifs using molecular dynamics and histogram methods

“…The different behavior of the palladium-silver clusters has been further studied dynamically by means of an order parameter defined as a species-centric order parameter by Hewage and Amar [59]. This shows the change of the center particle with the time as the simulation progresses.…”