Electric Field

[WEI Wei]

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!

[Daniele Varsano]

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

[WEI Wei]

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?

[Daniele Varsano]

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

Daniele

[WEI Wei]

Dear Daniele,

OK, I see. Thank you very much!