Yambo Community Forum

Dear All,

I have finished a G0W0 calculation with the command line of yambo -g n -p p. The input file shows:
----------------------------------------------------------------------------------------------------------------
gw0 # [R GW] GoWo Quasiparticle energy levels
ppa # [R Xp] Plasmon Pole Approximation
HF_and_locXC # [R XX] Hartree-Fock Self-energy and Vxc
em1d # [R Xd] Dynamical Inverse Dielectric Matrix
EXXRLvcs= 11733 RL # [XX] Exchange RL components
% QpntsRXp
1 | 43 | # [Xp] Transferred momenta
%
% BndsRnXp
1 | 250 | # [Xp] Polarization function bands
%
NGsBlkXp= 400 RL # [Xp] Response block size
% LongDrXp
1.000000 | 0.000000 | 0.000000 | # [Xp] [cc] Electric Field
%
PPAPntXp= 27.21138 eV # [Xp] PPA imaginary energy
% GbndRnge
1 | 200 | # [GW] G[W] bands range
%
GDamping= 0.100000 eV # [GW] G[W] damping
dScStep= 0.100000 eV # [GW] Energy step to evalute Z factors
DysSolver= "n" # [GW] Dyson Equation solver (`n`,`s`,`g`)
%QPkrange # [GW] QP generalized Kpoint/Band indices
1| 43| 14|21|
%
%QPerange # [GW] QP generalized Kpoint/Energy indices
1| 43| 0.0|-1.0|
%
----------------------------------------------------------------------------------------------------------------
As we can see, the Electric Field was set as:
------------------------------------------
%"LongDrXp
1.000000 | 0.000000 | 0.000000 | # [Xp] [cc] Electric Field".
%
------------------------------------------
BUT, it printed at the end of the "r_HF_and_locXC_em1d_ppa_gw0" file as:
------------------------------------------
"% LongDrXp
0.1000E-4 | 0.000 | 0.000 | # [Xp] [cc] Electric Field
%
-------------------------------------------
So, can you please tell me the reason of this difference?
Thank you very much!

Dear Wei Wei,
do not worry about that. In the input file you specify just the direction.
Next, you need a limit to q-->0, so you have the small value of q reported.

Cheers,

Daniele

Dear Daniele,

Thank you so much for your reply!
So, it means that there is no difference for a QP correction calculation with different directions of the electric field?

Dear Wei Wei,
it depends on your system, if it's highly anysotropic it could make some differences,
usually it does not.

Daniele

Dear Daniele,

OK, I see. Thank you very much!