Berlin 2008 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 21: POSTERS Colloids, Nanoparticles and Aggregates
CPP 21.13: Poster
Mittwoch, 27. Februar 2008, 16:00–18:30, Poster A
Metal salt-nanoparticle formation in supercritical water investigated by molecular dynamics simulation — •Norbert Lümmen and Bjørn Kvamme — University in Bergen, Institute for Physics and Technology, Allégaten 55, N-5007 Bergen, Norway
Nanoparticle formation of FeCl2 and MnCl2 from single ions in water at supercritical conditions was investigated by molecular dynamics (MD) simulations. The water-water interaction was modelled by the rigid SPC/E water model while the water-ion and ion-ion interaction was treated by a combination of Coulomb and Lennard-Jones potentials. The temperature was controlled by a heat bath thermostat using the Nosé-Hoover mechanism. The system density was chosen to match a system pressure around 25 MPa. Simulations at different heat bath temperature and system density were carried out while keeping the water to ion ratio constant.
Our results show that initial particle formation takes place within a few tens of picoseconds after the jump from ambient to supercritical conditions. Nucleation, surface growth and growth by cluster-cluster-collisions is observed. We present results on the time development of distributions of cluster sizes, cluster compositions, and cluster temperatures as well as radial distribution functions and nucleation rates.