Yambo Community Forum

Dear all
I run BSE.in and actually find the two warning in following:

<---> [01] Files & I/O Directories
<---> [02] CORE Variables Setup
<---> [02.01] Unit cells
<---> [02.02] Symmetries
<---> [02.03] RL shells
<---> [02.04] K-grid lattice
<---> [02.05] Energies [ev] & Occupations
<---> [03] Transferred momenta grid
<---> [M 0.170 Gb] Alloc bare_qpg ( 0.156)
<---> [04] Coloumb potential Random Integration (RIM)
<---> [05] Coloumb potential CutOff :box
<03s> Box |####################| [100%] 02s(E) 02s(X)
<03s> [06] External QP corrections (X)
<03s> [07] Static Dielectric Matrix
<03s> [08] External QP corrections (K)
<04s> [WARNING] W size reduced due to symmetry constraints
<04s> [BSE-W] W size forced by symmetry to be : 215
<04s> [09] Bethe-Salpeter Kernel
<04s> [RESTARTer] Section(s) completed for ./SAVE//db.BS_Q1 :9
<04s> [BSE] Kernel dimension : 71604
<04s> [09.01] Screened interaction header I/O
<49s> Filling Estimation |####################| [100%] 44s(E) 44s(X)
<49s> [P 01] Kernel filling [o/o] 100.0000
<49s> [WARNING]Exchange FFT size is too big. RL vectors reduced to 1007
<49s> [M 0.521 Gb] Alloc WF ( 0.351)
<49s> [FFT-BSK] Mesh size: 14 14 44
<54s> [WF-BSK loader] Wfs (re)loading |## | [014%] 05s(E) 35s( <59s> [WF-BSK loader] Wfs (re)loading |##### | [029%] 10s(E) 34s( <01m-04s> [WF-BSK loader] Wfs (re)loading |######### | [045%] 15s(E) <01m-09s> [WF-BSK loader] Wfs (re)loading |############ | [060%] 20s(E) <01m-15s> [WF-BSK loader] Wfs (re)loading |############### | [075%] 25s(E) <01m-20s> [WF-BSK loader] Wfs (re)loading |################## | [091%] 31s(E) <01m-22s> [WF-BSK loader] Wfs (re)loading |####################| [100%] 33s(E) 33s(X)
<01m-24s> [M 0.647 Gb] Alloc BS_W ( 0.125)
<01m-25s> [09.01] Main loop
-----------------------------------------------------------------------
# __ __ ______ __ __ _______ ______
# | \ / \ / \ | \ / \| \ / \
# \$$\ / $$| $$$$$$\| $$\ / $$| $$$$$$$\| $$$$$$\
# \$$\/ $$ | $$__| $$| $$$\ / $$$| $$__/ $$| $$ | $$
# \$$ $$ | $$ $$| $$$$\ $$$$| $$ $$| $$ | $$
# \$$$$ | $$$$$$$$| $$\$$ $$ $$| $$$$$$$\| $$ | $$
# | $$ | $$ | $$| $$ \$$$| $$| $$__/ $$| $$__/ $$
# | $$ | $$ | $$| $$ \$ | $$| $$ $$ \$$ $$
# \$$ \$$ \$$ \$$ \$$ \$$$$$$$ \$$$$$$
#
# GPL Version 3.2.5 Revision 1015
# http://www.yambo-code.org
#
em1s # [R Xs] Static Inverse Dielectric Matrix
optics # [R OPT] Optics
bse # [R BSK] Bethe Salpeter Equation.
bss # [R BSS] Bethe Salpeter Equation solver
rim_cut # [R RIM CUT] Coulomb interaction
setup # [R INI] Initialization
StdoHash= 20 # [IO] Live-timing Hashes
Nelectro= 34.00000 # Electrons number
FFTGvecs= 3000 RL # [FFT] Plane-waves
MaxGvecs= 1000 RL # [INI] Max number of G-vectors planned to use
NonPDirs= "none" # [X/BSS] Non periodic chartesian directions (X,Y,Z,XY...)
RandQpts=1000000 # [RIM] Number of random q-points in the BZ
RandGvec=1 RL # [RIM] Coulomb interaction RS components
#QpgFull # [F RIM] Coulomb interaction: Full matrix
% Em1Anys
0.00 | 0.00 | 0.00 | # [RIM] X Y Z Static Inverse dielectric matrix
%
IDEm1Ref=0 # [RIM] Dielectric matrix reference component 1(x)/2(y)/3(z)
CUTGeo= "box z" # [CUT] Coulomb Cutoff geometry: box/cylinder/sphere
% CUTBox
0.00 | 0.00 | 66.00 | # [CUT] [au] Box sides
%
CUTRadius= 0.000000 # [CUT] [au] Sphere/Cylinder radius
CUTCylLen= 0.000000 # [CUT] [au] Cylinder length
#CUTCol_test # [CUT] Perform a cutoff test in R-space
KfnQPdb= "none" # [EXTQP BSK BSS] Database
KfnQP_N= 1 # [EXTQP BSK BSS] Interpolation neighbours
% KfnQP_E
0.300000 | 1.000000 | 1.000000 | # [EXTQP BSK BSS] E parameters (c/v) eV|adim|adim
%
% KfnQP_Wv
0.00 | 0.00 | 0.00 | # [EXTQP BSK BSS] W parameters (valence) eV|adim|eV^-1
%
% KfnQP_Wc
0.00 | 0.00 | 0.00 | # [EXTQP BSK BSS] W parameters (conduction) eV|adim|eV^-1
%
KfnQP_Z= ( 1.000000 , 0.000000 ) # [EXTQP BSK BSS] Z factor (c/v)
BSresKmod= "xc" # [BSK] Resonant Kernel mode. (`x`;`c`;`d`)
BScplKmod= "none" # [BSK] Coupling Kernel mode. (`x`;`c`;`d`;`u`)
% BSEBands
1 | 30 | # [BSK] Bands range
%
BSENGBlk= 400 RL # [BSK] Screened interaction block size
BSENGexx= 6000 RL # [BSK] Exchange components
#ALLGexx # [BSS] Force the use use all RL vectors for the exchange part
% BSEEhEny
-1.000000 |-1.000000 | eV # [BSK] Electron-hole energy range
%
XfnQPdb= "none" # [EXTQP Xd] Database
XfnQP_N= 1 # [EXTQP Xd] Interpolation neighbours
% XfnQP_E
0.000000 | 1.000000 | 1.000000 | # [EXTQP Xd] E parameters (c/v) eV|adim|adim
%
% XfnQP_Wv
0.00 | 0.00 | 0.00 | # [EXTQP Xd] W parameters (valence) eV|adim|eV^-1
%
% XfnQP_Wc
0.00 | 0.00 | 0.00 | # [EXTQP Xd] W parameters (conduction) eV|adim|eV^-1
%
XfnQP_Z= ( 1.000000 , 0.000000 ) # [EXTQP Xd] Z factor (c/v)
% QpntsRXs
1 | 91 | # [Xs] Transferred momenta
%
% BndsRnXs
1 | 300 | # [Xs] Polarization function bands
%
NGsBlkXs= 400 RL # [Xs] Response block size
CGrdSpXs= 100.0000 # [Xs] [o/o] Coarse grid controller
% EhEngyXs
-1.000000 |-1.000000 | eV # [Xs] Electron-hole energy range
%
% LongDrXs
0.1000E-4 | 0.000 | 0.000 | # [Xs] [cc] Electric Field
%
DrudeWXs= ( 0.00 , 0.00 ) eV # [Xs] Drude plasmon
BSSmod= "h" # [BSS] Solvers `h/d/i/t`
% BEnRange
0.00000 | 7.00000 | eV # [BSS] Energy range
%
% BDmRange
0.0100 | 0.1000 | eV # [BSS] Damping range
%
BEnSteps= 700 # [BSS] Energy steps
% BLongDir
1.000000 | 0.000000 | 0.000000 | # [BSS] [cc] Electric Field
%
BSHayTrs= -0.02000 # [BSS] [o/o] Haydock treshold. Strict(>0)/Average(<0)
#BSHayTer # [BSS] Terminate Haydock continuos fraction
---------------------------


Best Regards
Davoud Vahedi,

Dept. of Physics,
Faculty of Science,
Ferdowsi University of Mashhad ,
Mashhad ,
Iran .

Dear Davoud,
please note that you asked for FFT Gvec (3000) more than the max allowed as you set MaxGvecs=1000.
MaxGvec is the maximum number of G-vec you are planning to use in all calculations. If you want
to use more than that you have to remove that variables. and probably rerun the setup if you included this
variable also in the setup run.

Best,

Daniele

Dear Varsano
Thank you for reply.I have other quastions. I read paper (Coupling of excitons and defect states in boron-nitride nanostructures,PHYSICAL REVIEW B 83, 144115 (2011)
) and have many quastions.
1-in Ref. 43 "40000 G vectors for the exchange" and "35000 for the correlation part of the self-energy ", These numbers are in accordance with one of the parameters in GW runlevel ?

2-in Ref. 44 "3000 bands" and "3833 G vectors for the dielectric matrix",
and "35000 G vectors for the wave functions", These numbers are in accordance with one of the parameters in BSE runlevel ?

3-in Ref. 45 "bands 300 to 500" and "10 eV cutoff on the electron-hole pair energy" and "20000 G vectors for the electronic wave functions", These numbers are in accordance with one of the parameters in BSE runlevel ?

Best Regards

Dear Davood,
my answer to your questions is :
1) yes
2) yes
3) yes
Anyway if you want more details you should ask to some of the authors of that paper.
Best,

Daniele

Dear Marini
I read paper (Coupling of excitons and defect states in boron-nitride nanostructures,PHYSICAL REVIEW B 83, 144115 (2011)) and have many quastions.

1-In Ref. 43 "40000 G vectors for the exchange" and "35000 for the correlation part of the self-energy ", Which the parameters in GW runlevel in accordance with those?

2-In Ref. 44 "3000 bands" and "3833 G vectors for the dielectric matrix",
and "35000 G vectors for the wave functions", Which the parameters in BSE runlevel in accordance with those?

3-In Ref. 45 "bands 300 to 500" and "10 eV cutoff on the electron-hole pair energy" and "20000 G vectors for the electronic wave functions", Which the parameters in BSE runlevel in accordance with those?

Best Regards

Dear Davoud,

1-In Ref. 43 "40000 G vectors for the exchange" and "35000 for the correlation part of the self-energy ", Which the parameters in GW runlevel in accordance with those?

yambo -x
Exchnage: EXXRLvcs
Correaltion: NGsBlkXp

2-In Ref. 44 "3000 bands" and "3833 G vectors for the dielectric matrix",
and "35000 G vectors for the wave functions", Which the parameters in BSE runlevel in accordance with those?

yambo -b
Bands for the screening: BndsRnXs
G vector for the screening: NGsBlkXs
G-vec wave functiond: FFTGvecs

3-In Ref. 45 "bands 300 to 500" and "10 eV cutoff on the electron-hole pair energy" and "20000 G vectors for the electronic wave functions", Which the parameters in BSE runlevel in accordance with those?

yambo -k sex
ands in BSE: BSEBands
electron-hole pair energy: BSEEhEny
G vec for wfs: FFTGvecs


Hope it is clear,
Best,

Daniele

Dear Varsano,
Thank you for your reply,
We want to plot wave function of excitons.(output file of Hydrogen_chain in tutorial, ''o-BSE_RIM.exc_3d_1.xsf'').We use of ''XcrySden-1.4.1 bin-static'' version, but can not see exitons, we post figure of this output.

Dear Davood,
if your run of BSE and ypp was successful, you can plot the exciton wavefunction drawing the corresponding isosurfaces using
the tool datagrid of xcrysden.
You can have a look here:
http://www.xcrysden.org/doc/density.html
on how plot it. Once the isosurface is plotted, you can play with the isosurface value.

Cheers,

Daniele

Dear Daniele
Thank you for reply. My problem is solved.

Best Regards