A study of alloy solidification using Monte Carlo computer modeling is reported. This work was undertaken to study non-equilibrium segregation effects such as solute trapping and to gain insight into the interactions between atoms during solidification, which are responsible for these effects. Simulations have been carried out for various growth temperatures, growth rates, surface roughness, liquid diffusivity, equilibrium segregation coefficient, entropy of fusion, and composition of the liquid. Changes in the distribution coefficient (k-value) from the equilibrium value have been used as a measure of the departure of the behavior of the system from expectations based on equilibrium thermodynamics. The segregation coefficient increases with growth rate, and decreases with increasing liquid diffusivity. The dependence of k-value on various growth conditions is captured by the parameter beta, which is defined in Eq. (1). The simulation results are consistent with experiment, and can be described by the analytical model, which is presented in J. Crystal Growth, this issue. doi:10.1016/j.crysgro.2004.07.073. In the simulations, the occupancy of various interface site configurations was found to be relatively independent of growth rate. The k-value was found to increase for liquid concentrations greater than about 10%. (C) 2004 Elsevier B.V. All rights reserved.