Resonant Charge Transfer in Hyperthermal Atomic and Molecular Ion- Surface Collisions
Abstract
We have investigated the interactions of hyperthermal (few to several hundred eV) atomic ions with metal surfaces, in particular the dynamics of electron transfer between the particle and surface. Progress is reported in the following areas: (1) construction of a time-of-flight spectrometer for measuring energy- and angle-resolved distributions of neutral and charged alkali atoms; (2) measurements of the magnitude and velocity-dependence of the neutralization probabilities for Li, Na, and K scattered from clean Cu(001); dramatic differences for Li, Na, and K reflect the sensitivity of nonadiabatic charge transfer to the energies and lifetimes of atomic electronic states near the surface; (3) measurements of branching ratios for Li(+), Li(-) and ground- and excited state (Li(2s) & Li(2p)) formation in Li(+) scattering from alkali- covered Cu(001), which provide a test of new multi-state charge transfer models and indicate some of the first evidence of multi-state effects in atom-surface charge transfer; (4) extensions of our multi-state studies to include formation of higher energy excited states of Li and Na, and multiple states in O(+) and O(+2) scattering; (5) observation of trajectory-dependent charge transfer for 50 eV Na(+) scattering from clean Cu(001); evidence is found for modification of the neutralization due to collision-induced defect formation in the surface; (6) preliminary measurements of trapping probabilities for 10-100 eV Na(+) scattering from clean Cu(001), which show a strong nonmonotonic dependence on the incident energy. These studies are part of a new program to investigate the mechanisms by which hyperthermal energy ion beams can be used to modify thin film growth.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 23, 1994
- Accession Number
- ADA284937
Entities
People
- Barbara H. Cooper
Organizations
- Cornell Laboratory of Atomic and Solid State Physics