The formation probability of secondary ions released from a metal surface under bombardment with a 20-keV cluster ion beam is investigated using combined time-of-flight secondary ion and neutral mass spectrometry (Tof-SIMS/SNMS) experiments. The emitted neutral atoms and clusters are post-ionized after their ejection using strong-field photoionization in an intense short infrared laser pulse. Comparing the secondary ion signal with that of the corresponding neutral particles, the ionization probability of sputtered indium atoms and Inn clusters with n = 2–4 is determined. The results are compared between two different projectile cluster ions, namely i) C60 + and ii) Arn + with n∼1000. It is shown that the ionization probability obtained with the fullerene cluster is by roughly a factor 4 larger than that obtained with the rare gas cluster, thereby indicating that there is no nonlinear enhancement of the transient electronic excitation generated by a cluster impact.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physical and Theoretical Chemistry