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W.S.M. Werner, K. Glantschnig, C. Ambrosch-Draxl:
"Optical Constants and Inelastic Electron-Scattering Data for 17 Elemental Metals";
Jounral of Physical and Chemical Reference Data, 38 (2009), 4; 1013 - 1092.

Two new sets of optical data, i.e., values for the real 1 and imaginary 2 parts of
the complex dielectric constant as well as the energy loss function ELF Im Å|1/ , are
presented for 16 elemental metals Ti, V, Fe, Co, Ni, Cu, Zn, Mo, Pd, Ag, Ta, W, Pt, Au,
Pb, and Bi and 1 semimetal Te and are compared to available data in the literature. One
data set is obtained from density functional theory DFT calculations and gives from
the infrared to the soft x-ray range of wavelengths. The other set of optical constants,
derived from experimental reflection electron energy-loss spectroscopy REELS spectra,
provides reliable optical data from the near-ultraviolet to the soft x-ray regime. The two
data sets exhibit very good mutual consistency and also, overall, compare well with
optical data found in the literature, most of which were determined several decades ago.
However, exceptions to this rule are also found in some instances, some of them systematic,
where the DFT and REELS mutually agree significantly better than with literature
data. The accuracy of the experimental data is estimated to be better than 10% for the
ELF and 2 as well as for 1 for energies above 10 eV. For energies below 10 eV, the
uncertainty in 1 in the experimental data may exceed 100%, which is a consequence of
the fact that energy-loss measurements mainly sample the absorptive part of the dielectric
constant. Electron inelastic-scattering data, i.e., the differential inverse inelastic mean free
path IMFP as well the differential and total surface excitation probabilities are derived
from the experimental data. Furthermore, the total electron IMFP is calculated from the
determined optical constants by employing linear response theory for energies between
200 and 3000 eV. In the latter case, the consistency between the DFT and the REELS
data is excellent better than 5% for all considered elements over the entire energy range
considered and a very good agreement with earlier results is also obtained, except for a
few cases for which the earlier optical data deviate significantly from those obtained
here.

dielectric function; density functional theory; electron scattering.