Internal Excitation Mechanisms of Neutral Atoms and Molecules Emitted from Ion Bombarded Organic Thin Films

摘要

Resonance enhanced laser photoionization schemes are employed to ionize C_6H_6 molecules and Ag atoms desorbed from Ag{111} by 8 keV Ar~+ ion bombardment.These schemes allow for probing ground state and internally excited species.Time-of-flight mass spectrometry is utilized to detect the postionized atoms and molecules desorbed in a neutral charge state and for determining their kinetic energy distributions from time-of-flight measurements.We find that internally excited species must originate from near the surface/vacuum interface.The species detected in the ground state may originate from deeper in the sample matrix,as well as from the surface.