MCMC2 : A Monte Carlo code for multiply-charged clusters
Résumé
We have implemented a Monte Carlo code in reduced units providing structural and thermodynamical properties of multiply-charged Lennard-Jones droplets ANn+, composed of N individual particles among which n are charged particles, each one carrying a charge qi (qi can be positive or negative). The cluster has a total net charge Q=Σi=1,nqi (Q > 0 or Q < 0). The interactions between particles are modelled by a sum of pairwise Lennard-Jones potentials and electrostatic terms, including polarisation. The cluster statistical properties can be obtained from (i) parallel Monte Carlo simulations whose replicas are run at different temperatures, from configurations with same number of charged particles n and same individual charges qi (Parallel Tempering Monte Carlo), or (ii) parallel Monte Carlo simulations whose replicas are run at the same temperature but from configurations with different qi or n (Parallel Charging Monte Carlo). The code provides statistical data (evaporation rates, acceptance/rejection rates, etc.), energetic data (mean energies, heat capacities, etc.), and structural data (radial and angular distributions), for comprehensive analyses. A complete manual of the code is provided.