The processes involved in soot precursor formation exhibit a wide range of timescales, spanning pico- or nanoseconds for intramolecular processes that can occur on a particle surface to milliseconds for the formation of the first soot precursors. To accurately describe the soot formation process, it is important to model the reactions happening at different timescales. The use of atomistic models allows this. The code, named KMC/MD, combines the strengths of Kinetic Monte Carlo for long-time sampling, and Molecular Dynamics for relaxation processes. It enables the investigation of physical as well as chemical properties of the carbonaceous nanoparticles formed, such as particle morphology and concentration of free radicals.