RF response similar to optical properties of Si

[amitwsu]

My question is based on the tutorial on Optical properties calculation with Meta-GGA. In that example Qwise calculates the optical spectrum followed by 'n' and 'k'.
Can the same approach be used to compute complex-epsilon in MHz or GHz  range or other frequency ranges?  Or is the underlying theory only applicable in the optical range?

Thanks in advance.
Amit

[Jess Wellendorff]

The OpticalSpectrum computes the susceptibility tensor using the Kubo-Greenwood formula and linear response assumptions. All other response properties are derived from that tensor. I am not sure if computing the complex dielectric constant at high energies goes beyond linear response. You should probably read the ATK Reference Manual entries for OpticalSpectrum and optical response functions to figure it out:
http://www.quantumwise.com/documents/manuals/latest/ReferenceManual/index.html/ref.opticalspectrum.html
http://www.quantumwise.com/documents/manuals/latest/ReferenceManual/index.html/chap.appendix.html#sect1.appendix.optical