Modelling in chimica computazionale: ottimizzazione di codici MD ed applicazioni allo studio di sistemi ad elevata carica

M.DynaMix is a modular general purpose Molecular Dynamics code for simulations of arbitrary mixtures of either rigid or flexible molecules. For its features and capabilities, M.DynaMix is diffused in a large simulation community and it is worth to keep it efficient and updated. With this goal in mind, a major revision of the package has been performed, leading to a version where several enhancements have been added: two efficient grid-based algorithm for long range interactions, SPME and ENUF, are now available; besides, a version of the code runnable on multi graphics boards has been produced. With the new features, the program exhibits a remarkable increase of computational efficiency and an improvement in global performance. The new version of M.DynaMix has been applied for studying some selected high charged particle system: DNA oligomers and ionic liquids. For oligomers, interactions between DNA and counterions has been investigated, searching for sequence dependent features. For ionic liquids, we focused on 1-decyl-3-methil-imidazolium chloride, to find a proper Force Field parameter set for its description. In both cases, the problem of validation of MD simulations has been treated, testing a new technique based upon the determination of quadrupolar decay parameters, for direct comparison between simulation and experiments.