Collision frequency of electrons in laser excited small clusters

Laser excited small metallic clusters are simulated using classical pseudo potential molecular dynamics simulations. Time-dependent distribution functions are obtained from the electron and ion trajectories in order to investigate plasma properties. The question of local thermodynamic equilibrium is addressed, and size effects are considered. Results for the electron distribution in phase space are given, which are interpreted within equilibrium statistical physics. Momentum autocorrelation functions were calculated for different cluster sizes and for different expansion states from the expanding system after the laser–cluster interaction. A resonance behaviour of the autocorrelation function in finite systems was observed. First, results concerning collision frequencies in small clusters are given.