Optical Constants of Nobel Metals _Drude Model_CST_Microwave

I have a question regarding the Optical Constants of Nobel Metals

According to [Johnson Christys Physical Review Paper on Optical Constants of Nobel Metals][1] the Drude free electron theory -- equation is

epsilon(omega)=1-((omega_p)^2)/(omega(omega+j*(1/taw)) ε=1-[(ωp)^2/(ω(ω+iγ))]
where epsilon(omega)= dielectric constants, omega=frequency,omega_p=plasma frequency, taw=Collision Frequency.

in [nanohub photonics database][2] the constants can be calculated from different theoretical and experimental models.

But in CST microwave Studio we need to place the epsilon infinity value.. which really comes from modified drude model

ε=ε(inf)-[(ωp)^2/(ω^2+iγω))] . for Gold how to get the values. Is there any reference by using which we can directly convert the free electron theory drude model to modified drude model.

I am searching for the values of ε(inf), ωp, γ for Gold at 700nm to 1100 nm range (specifically 830nm).




[1]: **broken link removed**
[2]: https://nanohub.org/tools/photonicsdb/

You can use matlab to caculate it, code can download @ https://www.mathworks.com/matlabcen...r-the-dielectric-constant-of-metals-and-water