Homogeneous argon condensation is modeled in a free expansion jet with a particle method. Microscopic kinetic models are used to simulate nucleation process, collisional processes among clusters and monomers, and evaporation of monomers from clusters. These models are integrated into the direct simulation Monte Carlo (DSMC) method to simulate an axisymmetric argon expansion coupled with condensation. Experimental data is used to correct the nucleation transient time, nucleation rate, and the condensation coefficient in the nucleation model. The corrected model is then, for the first time, applied to predict the distribution of Rayleigh scattering intensity in a free expansion argon condensation plume.