Ypp bug while analyzing excitons
Posted: Wed Mar 29, 2017 9:58 am
Dear Yambo developers,
I am using ypp -e s for sorting the excitons and ypp -e a for obtaining their amplitude (still from the 3.4.2 suite, the old-fashioned version
). During the calculation, I provided band manipulation parameters (scissor, stretching of VB and CB).
I found that the amplitudes obtained are not consistent with the underlying RPA-spectrum, as the band manipulations are not applied. When I manually apply the band manipulation, things become more consistent:
The first, optically active exciton (straight line) vs. the contribution of the electronic states: As the exciton is strongly bound, these should not be the respective states. The first, optically active exciton (straight line) vs. the contribution of the electronic states with band manipulations: This looks much better now. The contribution of the electronic states relevant for the first exciton to the RPA-spectrum: It even looks consistent. I think that band manipulation should be applied by ypp automatically at this point. (Or: does one have to supply the manipulation parameters again as they are only stored in the yambo-input?). The "problem": Valence and conduction band are stretched differently, which cannot be easily restored after the anaqlysis.
Kind regards!
Christian Wagner
P.S. My ypp-inputfile
And my BSE inputfile
I am using ypp -e s for sorting the excitons and ypp -e a for obtaining their amplitude (still from the 3.4.2 suite, the old-fashioned version
). During the calculation, I provided band manipulation parameters (scissor, stretching of VB and CB). I found that the amplitudes obtained are not consistent with the underlying RPA-spectrum, as the band manipulations are not applied. When I manually apply the band manipulation, things become more consistent:
The first, optically active exciton (straight line) vs. the contribution of the electronic states: As the exciton is strongly bound, these should not be the respective states. The first, optically active exciton (straight line) vs. the contribution of the electronic states with band manipulations: This looks much better now. The contribution of the electronic states relevant for the first exciton to the RPA-spectrum: It even looks consistent. I think that band manipulation should be applied by ypp automatically at this point. (Or: does one have to supply the manipulation parameters again as they are only stored in the yambo-input?). The "problem": Valence and conduction band are stretched differently, which cannot be easily restored after the anaqlysis.
Kind regards!
Christian Wagner
P.S. My ypp-inputfile
Code: Select all
# | excitons # [R] Excitons
# | amplitude # [R] Amplitude
# | BoseTemp= 0.02585 eV # Bosonic Temperature
# | States= "28 - 28" # Index of the BS state(s)
# | Degen_Step= 0.000000 eV # Maximum energy separation of two degenerate states
Code: Select all
optics # [R OPT] Optics
bse # [R BSE] Bethe Salpeter Equation.
bsk # [R BSK] Bethe Salpeter Equation kernel
bss # [R BSS] Bethe Salpeter Equation solver
em1s # [R Xs] Static Inverse Dielectric Matrix
rim_cut # [R RIM CUT] Coulomb interaction
NonPDirs= "XY" # [X/BSS] Non periodic chartesian directions (X,Y,Z,XY...)
Chimod= "Hartree" # [X] IP/Hartree/ALDA/LRC/BSfxc
BSEmod= "causal" # [BSE] resonant/causal/coupling
BSKmod= "SEX" # [BSE] IP/Hartree/HF/ALDA/SEX
BSSmod= "d" # [BSS] (h)aydock/(d)iagonalization/(i)nversion/(t)ddft`
WRbsWF # [BSS] Write to disk excitonic the FWs
BSENGexx= 40000 RL # [BSK] Exchange components
BSENGBlk= 611 RL # [BSK] Screened interaction block size
#WehCpl # [BSK] eh interaction included also in coupling
RandQpts= 0 # [RIM] Number of random q-points in the BZ
RandGvec= 1 RL # [RIM] Coulomb interaction RS components
CUTGeo= "cylinder z" # [CUT] Coulomb Cutoff geometry: box/cylinder/sphere
CUTradius=18.4000 # [CUT] [au] Sphere/Cylinder radius
CUTCylLen=0.0 # [CUT] [au] Cylinder length
% KfnQP_E
1.2317 | 1.0599 | 1.1479 | # [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)
% BEnRange
0.00000 | 10.00000 | eV # [BSS] Energy range
%
% BDmRange
0.012500 | 0.02500 | eV # [BSS] Damping range
%
BEnSteps= 200 # [BSS] Energy steps
% BLongDir
0.000000 | 0.000000 | 1.000000 | # [BSS] [cc] Electric Field
%
% BSEBands
55 | 74 | # [BSK] Bands range
%
% BndsRnXs
1 | 256 | # [Xs] Polarization function bands
%
NGsBlkXs= 611 RL # [Xs] Response block size
% LongDrXs
0.000 | 0.000 |0.1000E-4 | # [Xs] [cc] Electric Field
%