Homogeneous SPC/E water nucleation in large molecular dynamics simulations.

We perform direct large molecular dynamics simulations of homogeneous SPC/E water nucleation, using up to ∼ 4 ⋅ 106 molecules. Our large system sizes allow us to measure extremely low and accurate nucleation rates, down to ∼ 1019 cm−3 s−1, helping close the gap between experimentally measured rates ∼ 1017 cm−3 s−1. We are also able to precisely measure size distributions, sticking efficiencies, cluster temperatures, and cluster internal densities. We introduce a new functional form to implement the Yasuoka-Matsumoto nucleation rate measurement technique (threshold method). Comparison to nucleation models shows that classical nucleation theory over-estimates nucleation rates by a few orders of magnitude. The semi-phenomenological nucleation model does better, under-predicting rates by at worst a factor of 24. Unlike what has been observed in Lennard-Jones simulations, post-critical clusters have temperatures consistent with the run average temperature. Also, we observe that post-critical clusters have dens...