| Molecular dynamics is used to do extensive simulations of a three-dimensional, two component Lennard-Jones mixture that is a model glass former. I find that the behavior of the system near the glass transition is consistent with a near-mean-field interpretation. In this interpretation, the glass transition is associated with an underlying liquid-solid pseudospinodal. A spinodal is a thermodynamic instability that exists only in the mean-field limit; a pseudospinodal is the remnant of this instability for systems with effective long-range interactions.; The behavior of the self-diffusion coefficient as a function of temperature can be fit to a power law at high temperatures in agreement with mode coupling theory, but I find that a Vogel-Fulcher dependence fits over a wider range of temperatures. The first peak of the static structure function is found to grow near the pseudospinodal and can be fit to a weak divergence as predicated by the theory. Using a novel cluster definition, I have identified clusters of solid-like particles. I find that the size distribution of the clusters ns, can be fit to a power law times an exponential cutoff at high temperatures. The resulting exponent is close to −3/2, the value predicted for critical fluctuations near a spinodal. At temperatures closer to the pseudospinodal, ns can be fit to a simple power law with an exponent close to −2, consistent with the predicted distribution of arrested spinodal nucleation droplets. The near-mean-field interpretation also implies that there should be a growing length near the pseudospinodal. Although I was unable to find such a length that was independent of the clusters, the cluster connectedness length diverges as the pseudospinodal is approached. |
