We present here simulation results of the laser-driven acceleration of gold ions using the EPOCH code. Recently, an experiment reported the acceleration of gold ions up to 7 MeV/nucleon with a strong dependency of the charge-state distribution on target thickness and the detection of the highest charge states $${\text {Z}} \sim 72$$ Z ∼ 72 . Our simulations using a developmental branch of EPOCH (4.18-Ionization) show that collisional ionization is the most important cause of charge states beyond Z = 51 up to He-like Au.