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Ion specific effects are ubiquitous. The term denotes the fact that most processes in
electrolyte solutions not only depend on ion concentration and valency, but also on the ion
type.
In the first part of my talk, I provide insight into the origin of ion specific effects by
combining results from molecular dynamics simulations and Poisson– Boltzmann theory at surfaces
containing non-polar, polar and charged functional groups. This allows us to quantify ion-specific
binding affinities to surface groups of varying polarity and charge, and to provide a connection to
the experimentally measured long-ranged electrostatic forces that stabilize colloids, proteins and
other biomolecules.
In the second part of my talk, I focus on the interaction of metal cations and RNA. To
investigate the role of different cations in RNA folding and function, an accurate parametrization
is crucial to capture the fine differences between distinct metal cations in classical all-atom
simulations. Using enhanced sampling techniques allows us to capture rare events and slow processes
like partial ion dehydration to form inner-sphere ion-pairs and to calculate ion binding affinities
as well as kinetic rate coefficients.
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