Bimodal equilibrium theory

Simulations—isoergic and isothermal, by molecular dynamics and Monte Carlo—as well as analytic theory have been used to study this process. The diagnostics that have been used include study of mean nearest interparticle distances, kinetic energy distributions, pair distribution functions, angular distribution functions, mean square displacements and diffusion coefficients, velocity autocorrelation functions and their Fourier transforms, caloric curves, and snapshots. From the simulations it seems that some clusters, such as Ar, 3 and Ar, 9, exhibit the double-valued equation of state and bimodal kinetic energy distributions characteristic of the phase change just described, but others do not. Another kind of behavior seems to occur with Arss, which exhibits a heterogeneous equilibrium, with part of the cluster liquid and part solid. 

For the calculation of the stability of a multicomponent polymer solution (spinodal line and critical solution points), the stability theory can be applied [42]. One possible consequence of the poiydispersity, especially if the distribution function is bimodal, is the appearance of tri-critical solution points [2]. Suggestions for the phase equilibrium calculations of such systems can be found in the literature [2, 39, 43). 

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