  We use a multiscale approach to study a lattice-gas model of submonolayer
growth of Fe/Mo(110) by Molecular Beam Epitaxy. To begin with, we construct a
two-dimensional lattice-gas model of the Fe/Mo(110) system based on
first-principles calculations of the monomer diffusion barrier and
adatom-adatom interactions. The model is investigated by equilibrium Monte
Carlo (MC) simulations to compute the diffusion coefficients of Fe islands of
different sizes. These quantities are then used as input to the coarse-grained
Kinetic Rate Equation (KRE) approach, which provides time evolution of the
island size distributions for a system undergoing diffusion driven aggregation
within the 2D submonolayer regime. We calculate these distributions at
temperatures T=500 K and 1000 K using the KRE method. We also employ direct
kinetic MC simulations of our model to study island growth at T=500 K, and find
good agreement with the KRE results, which validates our multi-scale approach.
