Yambo Community Forum

Dear Yambo Team,

Is is possible to obtain the static dielectric constant (frequency → 0) from the output of yambo? I want to use the hydrogen-like atom model for the exciton, but do not know how to get the static dielectric constant.

If yambo can do this job, then will the static dielectric constant be a complex number like its frequency-dependent counterpart, or reduced to a real number?

Best
Yunhai

Dear Yunhai,
You can obtain it at different level of theory, you need the dielectric matrix or the macroscopic quantity.
You can the obtain the macroscopic quantity (at different q, transfer momentum), in linear reponse (yambo -o c) -k option, looking the the value at zero frequency.
If you need all the component of the matrix,they are stored in the ./SAVE/ndb.em1s file which is calculated using the (yambo -b) input. You can read them by using
the ncdump command of netcdf libs.

Best,
Daniele