AVS 50th International Symposium
    Surface Science Monday Sessions
       Session SS1-MoM

Paper SS1-MoM9
Charge Exchange between Metal Ions and Surfaces

Monday, November 3, 2003, 11:00 am, Room 326

Session: Gas-Surface Dynamics
Presenter: X. Chen, University of California, Riverside
Authors: X. Chen, University of California, Riverside
J. Doan, University of California, Riverside
Z. Sroubek, Czech Academy of Science, Czech Republic
J.A. Yarmoff, University of California, Riverside
Correspondent: Click to Email
Ion-surface charge exchange is important in surface analytical methods that employ ion beams, such as ion scattering spectroscopy (ISS), secondary ion mass spectrometry (SIMS) and electron stimulated desorption (ESD). In earlier work, we showed that the probability for neutralization of an alkali ion scattered from a metal surface is determined by the local electrostatic potential (LEP) a few Å's above the scattering site. We are now extending this work to investigate homogeneous charge exchange between metal ions and identical metal surfaces. In the first set of experiments, Ar@sup +@ and Kr@sup +@ ions are used to induce direct recoil of fast Al from Al(100). The neutral fraction of the recoils is then measured with time-of-flight as a function of emission angle and energy. From this data, and with the aid of Monte-Carlo simulations using scattering and recoiling imaging code (SARIC),@footnote 1@ we can obtain information on homogeneous charge exchange processes. Adsorbates, such as Cs and O, will be used to modify the surface work function so that measured changes in neutralization can be used to further reveal the charge transfer process. In the next set of experiments, we are producing metal ion beams for scattering. Al ions are being produced in an Al(CH@sub 3@)@sub 3@ plasma, and Ga ions from a liquid metal ion source. Such pure metal ion beams will allow for simple scattering experiments in which a clear correlation between can be made neutralization and trajectory. @FootnoteText@ @footnote 1@ V. Bykov, C. Kim, M. M. Sung, K. J. Boyd, S. S. Todorov and J. W. Rabalais, Nucl. Instrum. Meth. B 114 (1996) 371.