  Grain growth experiments on thin metallic films have shown the geometric and
topological characteristics of the grain structure to be universal and
independent of many experimental conditions. The universal size distribution,
however, is found to differ both qualitatively and quantitatively from the
standard Mullins curvature driven model of grain growth; with the experiments
exhibiting an excess of small grains (termed an "ear") and an excess of very
large grains (termed a "tail") compared with the model. While a plethora of
extensions of the Mullins model have been proposed to explain these
characteristics, none have been successful. In this work, large scale
simulations of a model that resolves the atomic scale on diffusive time scales,
the phase field crystal model, is used to examine the complex phenomena of
grain growth. The results are in remarkable agreement with the experimental
results, recovering the characteristic "ear" and "tail" features of the
experimental grain size distribution. The simulations also indicate that while
the geometric and topological characteristics are universal, the dynamic growth
exponent is not.
