Laser ablation of bicomponent systems: A probe of molecular ejection mechanisms

A combined experimental and molecular dynamics simulation study of laser ab lation of a model bicomponent system with solutes of different volatility p rovides a consistent picture of the mechanisms of material ejection. The co mparison of the ejection yields shows that there are two distinct regimes o f molecular ejection, desorption at low laser fluences, and a collective ej ection of a volume of material or ablation at higher fluences. Ejection of volatile solutes dominates in the desorption regime, whereas nonvolatile so lutes are ejected only in the ablation regime. (C) 2001 American Institute of Physics.