title: Charge separation and isolation in strong water droplet impacts.
abstract: Charge separation in condensed matter after strong impacts is a general and intriguing phenomenon in nature, which is often identified and described but not necessarily well understood in terms of a quantitative mechanistic picture. Here we show that charge separation naturally occurs if water droplets/clusters or ice particles with embedded charge carriers, e.g., ions, encounter a high energy impact with subsequent dispersion - even if the involved kinetic energy is significantly below the molecular ionization energy. We find that for low charge carrier concentrations (c < 0.01 mol L(-1)) a simple statistical Poisson model describes the charge distribution in the resulting molecular "fragments" or aggregates. At higher concentrations Coulomb interactions between the charge carriers become relevant, which we describe by a Monte Carlo approach. Our models are compared to experimental data for strong (laser) impacts on liquid micro beams and discussed for the charge generation in cluster-impact mass spectrometry on cosmic dust detectors where particle kinetic energies are below the plasma threshold. Taken together, a simple and intuitive but quantitative microscopic model is obtained, which may contribute to the understanding of a larger range of phenomena related to charge generation and separation in nature.
authors: MPI für biophysikalische Chemie, Am Fassberg 11, 37077 Göttingen, Germany.
authors: F
authors: F
authors: Wiederschein
authors: E
authors: E
authors: Vöhringer-Martinez
authors: A
authors: A
authors: Beinsen
authors: F
authors: F
authors: Postberg
authors: J
authors: J
authors: Schmidt
authors: R
authors: R
authors: Srama
authors: F
authors: F
authors: Stolz
authors: H
authors: H
authors: Grubmüller
authors: B
authors: B
authors: Abel
mesh_terms: D007477:Ions / Q000737:chemistry; D008962:Models, Theoretical; D009010:Monte Carlo Method; D014867:Water / Q000737:chemistry*
chemical_list: D007477:Ions; D014867:Water