  Observations of galactic white dwarfs with Gaia have allowed for
unprecedented modeling of white dwarf cooling, resolving core crystallization
and sedimentary heating from neutron rich nuclei. These cooling sequences are
sensitive to the diffusion coefficients of nuclei in Coulomb plasmas which have
order 10\% uncertainty and are often not valid across coupling regimes. Using
large scale molecular dynamics simulations we calculate diffusion coefficients
at high resolution in the regime relevant for white dwarf modeling. We present
a physically motivated law for diffusion with a semi-empirical correction which
is accurate at the percent level. Implemented along with linear mixing in
stellar evolution codes, this law should reduce the error from diffusion
coefficients by an order of magnitude.
