Simulations of Extreme Ionization and Electron Dynamics in Ultraintense Laser–Cluster Interactions

We present a molecular dynamics (MD) simulation code for the exploration of extreme multielectron ionization and attosecond–femtosecond electron dynamics in elemental and molecular clusters driven by ultraintense (peak intensity I_M = 10 ¹⁵ –10 ¹⁶ W cm⁻²), ultrafast (temporal pulse widths τ = 10–100 fs), near infrared (photon frequency 0.35 fs⁻¹) laser fields. Validity conditions are presented for the applicability of classical MD simulations to high-energy electron dynamics, which rest on the localization of the wave packet and the distinguishability of identical particles. We also examine the cluster size domain for the applicability of the MD simulation code where the laser intensity is uniform inside the cluster.