  Via hydrodynamics preserving molecular dynamics simulations we study growth
phenomena in a phase separating symmetric binary mixture model. We quench
high-temperature homogeneous configurations to state points inside the
miscibility gap, for various mixture compositions. For compositions around the
symmetric or critical value we capture the rapid linear viscous hydrodynamic
growth due to advective transport of material through tube-like interconnected
domains. The focus of the work, however, is on compositions close to any of the
branches of the coexistence curve. In this case, the growth in the system,
following nucleation of droplets of the minority species, occurs via
coalescence mechanism. Using state-of-the-art techniques we have identified
that these droplets, between collisions, exhibit diffusive motion. The value of
the exponent for the power-law growth, related to this diffusive coalescence
mechanism, as the composition keeps departing from the critical value, has been
estimated. This nicely agrees with a theoretical number. These results are
compared with the growth that occurs via particle diffusion mechanism, in
non-hydrodynamic environment.
