Confusion on G0W0 Input Variables

[WEI Wei]

Dear all,

The yambo.in generated by command line of "yambo - g n -p p" is posted as following:
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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= 301 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
14 | 21 | # [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|
%

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But I was confused by two variables: "em1d" and "LongDrXp":
(1) Since the "em1d" (dynamical) will be calculated, does the "BndsRnXp" (static) make sense?
(2) What is the trick upon setting "LongDrXp"?

Thank you very much!

[myrta gruning]

Hallo Wei
There is no confusion.

The yambo.in generated by command line of "yambo - g n -p p"

You have asked for quasiparticle energies within the GW approximation using plasmon pole approximation for W (see the runlevels page)

Since the "em1d" (dynamical) will be calculated, does the "BndsRnXp" (static) make sense?

Then Xp is not the static (that would be Xs), but the "plasmon pole approximation" for X. You may look as well at the detailed description of the plasmon pole options.

Best,
m

[WEI Wei]

Dear Myrta,

Thank you very much for your reply and patience!
But I still have a question: Can I change the direction of electric field in a "yambo -g n -p p" calculation using the variable of "LongDrXp"? What and How does this change affect the QP energy correction?
----------------------------------------------------------------------
% LongDrXp
1.000000 | 0.000000 | 0.000000 | # [Xp] [cc] Electric Field
%
----------------------------------------------------------------------
I am looking farward to your reply.
Thank you very much, and have a nice weekend.

[myrta gruning]

Can I change the direction of electric field in a "yambo -g n -p p" calculation using the variable of "LongDrXp"? What and How does this change affect the QP energy correction?

Yes of course you can.
If the material is isotropic should not make any difference. If your material is highly anysotropic it may depend on the light polarization you want to look at.

Best
m.

[WEI Wei]

Dear Myrta,

OK, I see.
Thank you so much!