AVS 53rd International Symposium
    Applied Surface Science Thursday Sessions
       Session AS-ThP

Paper AS-ThP35
Calculations of Electron Inelastic Mean Free Paths In 12 Organic Compounds and 15 Inorganic Compounds Over the 50 - 30,000 eV Energy Range

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Aspects of Applied Surface Science Poster Session
Presenter: S. Tanuma, National Institute for Materials Science (NIMS), Japan
Authors: S. Tanuma, National Institute for Materials Science (NIMS), Japan
C.J. Powell, National Institute of Standards and Technology
D.R. Penn, National Institute of Standards and Technology
Correspondent: Click to Email
We have calculated electron inelastic mean free paths (IMFPs) for 50-30,000 eV electrons in 12 organic compounds (26-n-paraffin, adenine, beta-carotene, diphenyl-hexatriene, guanine, kapton, polyacetylene, poly(butene-1-sulfone), polyethylene, polymethylmethacrylate, polystyrene, and poly(2-vinylpyridine)) and 15 inorganic compounds (Al@sub 2@O@sub 3@, GaAs, GaP, H@sub 2@O, InAs, InP, InSb, KBr, KCl, LiF, MgO, NaCl, SiC, SiO@sub 2@, and ZnS)) using their energy-loss functions and the Penn algorithm. The new IMFPs were calculated at equal energy intervals on a logarithmic scale corresponding to increments of 10 %. These IMFPs could be fitted to the modified Bethe equation for inelastic scattering of electrons in matter for energies from 50 eV to 30,000 eV. The average RMS deviations in these fits were 0.12 % for the 12 organic compounds and 0.62% for the 15 inorganic compounds. These RMS values are almost the same as those found in our fits of IMFPs calculated previously for the 50 - 2000 eV energy range. The new IMFPs were also compared with IMFPs from the TPP-2M equation; the average RMS deviations were 8.1 % for the 12 organic compounds and 18.2 % for the 15 inorganic compounds in the 50 eV to 30,000 eV energy range. These RMS value are almost the same as those found (8.5% for inorganic and 19.1% for inorganic compounds) in similar comparisons for the 50 - 2000 eV energy range. Relatively large RMS deviations were found for LiF (47 %), GaAs (37 %), and InAs (26 %). We conclude that the TPP-2M equation is useful for IMFP estimation in other compounds for energies up to 30,000 eV with an average uncertainty of about 18 %.