AVS 45th International Symposium
    Applied Surface Science Division Thursday Sessions
       Session AS-ThM

Paper AS-ThM5
Evaluation of Calculated and Measured Electron Inelastic Mean Free Paths

Thursday, November 5, 1998, 9:40 am, Room 307

Session: Gaede-Langmuir Award Address and Quantitative Surface Analysis
Presenter: C.J. Powell, National Institute of Standards and Technology
Authors: A. Jablonski, Polish Academy of Sciences
C.J. Powell, National Institute of Standards and Technology
Correspondent: Click to Email
NIST will release a database in 1998 that provides values of electron inelastic mean free paths (IMFPs) for use in surface analysis by AES and XPS. The database includes IMFPs calculated from optical data and measured by elastic-peak electron spectroscopy. IMFPs can also be obtained from the predictive formulae proposed by Seah and Dench, Tanuma et al., and Gries. We present here an evaluation of calculated and measured IMFPs for seven elemental solids (Al, Si, Ni, Cu, Ge, Ag, and Au); these solids were selected because, for each, there were two or more independent IMFP calculations and two or more independent IMFP measurements. For each element, calculated IMFPs have been compared, measured IMFPs have been compared, and calculated and measured IMFPs have been compared. Our preliminary results indicate that the best agreement among the calculated IMFPs (as determined from mean relative deviations with respect to a common fitted curve) is found for Al, Ni, and Ag. Similarly, the best agreement among the experimental values is found for Si, Cu, and Ge, and the best agreement between calculated and measured values is found for Cu, Ag, and Au. We will discuss reasons for the differences found in our comparisons.