Extract frquency-depent dielectric function from SCR files

[gmatteo]

Dear All!
Have you tried to extract frquency-dependent dielectric function from SCR files?
How? Any suggestion would be appreciated!
YuanXun

[gmatteo]

There are two files that can be used to analyze optical properties within the RPA approximation.

o_EM_LF contains the real and imaginary part of the Macroscopic Dielectric Function with
local field effects included.
o_EM_NLF stores the macroscopic dielectric Function without local fields

Note that by default abinit uses the plasmon-pole technique thus only two frequencies
will be calculated in the screening run.
To have the dielectric function on a frequency mesh along the real axis, one has to use:

#Variables for optical properties
gwcalctyp 2 # one-shot G0W0 with contour_deformation
nfreqre 500 # No. of real frequencies in W
nfreqim 1 # No. of imag frequencies in W
freqremax 20 eV # Max real freq

The frequency mesh is linear and defined via nfreqre and freqremax.
nfreqim can be set to 1 if the knowledge of W along the imaginary axis is not needed
but the resulting SCR file cannot be used for self-energy calculations with
the contour deformation technique.

M