Quantitative electron spectroscopy of surfaces: A standard data base
for electron inelastic mean free paths in solids
Surf. Interface Anal., 1 (1):
2--11 (1979)DOI: 10.1002/sia.740010103
Abstract
A compilation is presented of all published measurements of electron
inelastic mean free path lengths in solids for energies in the range
0-10 000 eV above the Fermi level. For analysis, the materials are
grouped under one of the headings: element, inorganic compound, organic
compound and adsorbed gas, with the path lengths each time expressed
in nanometers, monolayers and milligrams per square metre. The path
lengths are vary high at low energies, fall to 0.1-0.8 nm for energies
in the range 30-100 eV and then rise again as the energy increases
further. For elements and inorganic compounds the scatter about a
üniversal curve" is least when the path lengths are expressed in
monolayers, lambdam. Analysis of the inter-element and inter-compound
effects shows that lambdam is related to atom size and the most accuratae
relations are lambdam = 538E-2+0.41(aE)1/2 for elements and lambdam=2170E-2+0.72(aE)1/2
for inorganic compounds, where a is the monolayer thickness (nm)
and E is the electron energy above the Fermi level in eV. For organic
compounds lambdad=49E-2+0.11E1/2 mgm-2. Published general theoretical
predictions for lambda, valid above 150 eV, do not show as good correlations
with the experimental data as the above relations.