Dear Myrta:

Thanks for reminding and clarification!

myrta gruning wrote:

just one addition to what Andrea said.

You are referring to the loss function as -$\Im[\chi_{G=0,G'=0}(q,\omega)]$, but the definition is $-Im(eps^{-1}(q,\omega)) = -v(q)Im[\chi_{G=0,G'=0}(q,\omega)$ (v Coulomb interaction), and this is the quantity you get from yambo.

In fact, i noticed this difference between my expression and the definition, which is also the reason i want to manipulate over the data to get the exact the curve for -$\Im[\chi_{G=0,G'=0}](q,\omega)$. But after i examined the formula and the data curve, i found things cannot be changed even i get -$\Im[\chi_{G=0,G'=0}](q,\omega)$ curve from yambo, since the curves for high transfer momenta are quite different from the published data . My data present some noice oscillations for hign transfer momenta even i increased energy steps and included more bands . The most important difference i found is that the so-called plasmon energy is not the same: mine is around 22 eV for (0.40, 0., 0.) (iku) while the paper giving is about 15.8 eV for (0.40, 0.0 ,0.0) $2\pi/a$.

By the way what does

iku exactly stands for ? In my situation, i just thought (0.40, 0., 0.0)(iku) was the same as

(0.40, 0.0 ,0.0) $2\pi/a$ .

Thanks again for time and patience!

Cheers,

Hai-Ping