calculation of dielectric function

[danial]

Hi,
first Special thanks to Dr.Blom and his colleagues to support this great program.

I have problem to calculate imaginary part of dielectric function for different intensity of external electric field across the plane of 2D monolayer silicene versus electric vector polarization along E⊥c.  these calculations are done in Siesta not in ATK  in  following paper(fig 8 of the paper).

http://www.sciencedirect.com/science/article/pii/S1386947713001872

is it possible to explain and help me to do that?

Thanks

[zh]

What has been done in the reference paper your mentioned  is the calculations of Optical Spectrum of a 2D material at a given external electric field.
http://www.quantumwise.com/documents/manuals/latest/ReferenceManual/index.html/ref.opticalspectrum.html

For the simulation of a 2D materials at a given external electric field, you can refer to the discussion at the following threads:
http://quantumwise.com/forum/index.php?topic=1561.msg7843#msg7843
http://quantumwise.com/forum/index.php?topic=2520.msg11745#msg11745

[danial]

Thanks for your response, your links help me so much.
I did those calculations, but my problem is calculate the Fine structure of imaginary part of dielectric like fig8 of the paper.
how can it possible?

Thank you in advanced 

[zh]

The figure 8 in that paper just shows the imaginary part of dielectric constant.

Once you have calculated the optical spectrum, the  imaginary part of dielectric constant can be easily obtained. Please refer to the formula written in the following webpage:
http://www.quantumwise.com/documents/manuals/latest/ReferenceManual/index.html/ref.opticalspectrum.html