A paper on new force field parameters for actinyl ions in water, written by group Vladimir Pomogaev, Surya Tiwari, and Neeraj Rai, along with collaborators George Goff and Wolfgang Runde at Los Alamos, has been published in Phys. Chem. Chem. Phys. (2013, 15, 15954-15963). The paper presents intra- and inter-molecular parameters for AnO2n+, where An = U, Np, Pu and Am and n=1 or 2.
The new potentials were used to carry out extensive molecular dynamics simulations for each hydrated ion. Computed bond lengths, bond angles and coordination numbers agree well with known values and previous simulations. Hydration free energies, computed from molecular dynamics simulations as well as from quantum simulations with a solvation model, were in reasonable agreement with estimated experimental values.
Figure showing typical arrangement of water about two actinyl ions.