Brooke Nielsen

We describe calculations of the structure of amorphous polyethylene oxide using a previously reported model, but with better treatment of hydrogen positions and in a code which allows relaxation of stresses in the polymerized sample by Rahman-Parrinello techniques. We also report the effects of two different intermolecular force field potentials and find that our earlier, empirical force field produces better agreement with experimental neutron scattering results than a force field derived from… Show more

We describe calculations of the structure of amorphous polyethylene oxide using a previously reported model, but with better treatment of hydrogen positions and in a code which allows relaxation of stresses in the polymerized sample by Rahman-Parrinello techniques. We also report the effects of two different intermolecular force field potentials and find that our earlier, empirical force field produces better agreement with experimental neutron scattering results than a force field derived from ab initio electronic structure calculations. Show less

In this program, simulation methods are used to study condensed matter interfaces.
Simulations of the electrode-electrolyte interface include the dynamics of the molecules during electron
transfer to or from the electrode, and the study of the electronic structure of oxides and metals at the
electrode-electrolyte interface using self-consistent tight binding molecular dynamics as well as ab
initio plane wave techniques. We are modeling the solvation, transport and ion pairing… Show more

In this program, simulation methods are used to study condensed matter interfaces.
Simulations of the electrode-electrolyte interface include the dynamics of the molecules during electron
transfer to or from the electrode, and the study of the electronic structure of oxides and metals at the
electrode-electrolyte interface using self-consistent tight binding molecular dynamics as well as ab
initio plane wave techniques. We are modeling the solvation, transport and ion pairing in
polymer electrolytes and their instances with battery electro density molecular dynamics techniques.
Finally, the interaction of gases with superfluid helium four and dilute Bose-Einstein condensed
systems. Show less

Our work was on the first three-dimensional MHD simulations of particle
transport and radiation from radio galaxies. These simulations include the acceleration and transport of
the relativistic electrons producing the observed emission. For the first time, we created a model of
a direct connection between the flow dynamics of the jets driving the phenomenon and observed
properties of the objects.

The structure of polyethylene oxide PEO was investigated by neutron scattering in both semicrystalline and liquid states. Deuterated samples were studied in addition to the protonated ones in order to avoid the large incoherent scattering of hydrogen and identify features in the pair correlation functions attributable to C–H pairs. Analysis of the deuterated sample gave additional information on the C–O and C–C pairs. The results are compared with molecular-dynamics simulations of liquid PEO.