On slide 19 of
http://susi.theochem.tuwien.ac.at/events/ws2017/notes/Laskowski_optic-xas.pdf
it has "broadening for Drude terms choose gamma for each case".
The above statement may be advising to do an extensive literature survey
for the specific structure under calculation.
Slide 20 has 0.1 for a metal and 0.05 for semiconductor.
When fitting a curve to experimental data such as in Origin [
https://my.originlab.com/forum/topic.asp?TOPIC_ID=10648 ], starting
guess values may be needed in the Values column in the fit window:
https://www.originlab.com/doc/Tutorials/Fitting-NLFit-Basic
Perhaps, those slide 20 values are typically a good starting guess value.
You might see if you can find the value in a table on online. For example:
See table under "Application to materials" in:
https://www.horiba.com/fileadmin/uploads/Scientific/Downloads/OpticalSchool_CN/TN/ellipsometer/Drude_Dispersion_Model.pdf
See Table 4 in article titled "Conductive nitrides: Growth principles,
optical and electronic properties, and their perspectives in photonics
and plasmonics":
https://doi.org/10.1016/j.mser.2017.11.001
See Table 1 and others in article titled "Fitting the optical constants
of gold, silver, chromium, titanium, and aluminum in the visible bandwidth":
https://doi.org/10.1117/1.JNP.8.083097
On 1/15/2021 6:26 PM, karima Physique wrote:
Dear WIEN2k users,
for intraband contribution, where can I find the value of Gamma for
Drude term
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