### BSE@GW: Null BSE kernel block dimension(s) found.

Posted:

**Tue Jul 23, 2019 4:07 pm**Dear all,

I was trying to do "self-consistent" GW (copy-paste ndb.QP method) and I am trying to perform BSE on top of that (I want to avoid scissoring the DFT data). However there is something strange happening in the BSE step (probably related to *ERR* messages in the report file): the input reported in the BSE report file is not the same as the input in the input file (-F input.in).

I think the GW step was successful as it gives me a gap of ~8 eV compared to the 4.5 eV@DFT level (system is a monolayer of BN, 12x12x1 kpnts, 200 bands, 4 valence bands); GW "converges" after 3-4 sc cycles.

My GW in file is

then I generate a BSE input file yambo -o b -k sex -y d -p p -V qp

my BSE input file is

but then the report file shows that there is apparently some mismatch and the BSE kernel can't be built

and further down some *ERR* messages

Are those ERR related to the failure of the BSE?

Thanks for your assistance!

Chris

I was trying to do "self-consistent" GW (copy-paste ndb.QP method) and I am trying to perform BSE on top of that (I want to avoid scissoring the DFT data). However there is something strange happening in the BSE step (probably related to *ERR* messages in the report file): the input reported in the BSE report file is not the same as the input in the input file (-F input.in).

I think the GW step was successful as it gives me a gap of ~8 eV compared to the 4.5 eV@DFT level (system is a monolayer of BN, 12x12x1 kpnts, 200 bands, 4 valence bands); GW "converges" after 3-4 sc cycles.

My GW in file is

Code: Select all

```
em1d # [R Xd] Dynamical Inverse Dielectric Matrix
gw0 # [R GW] GoWo Quasiparticle energy levels
ppa # [R Xp] Plasmon Pole Approximation
HF_and_locXC # [R XX] Hartree-Fock Self-energy and Vxc
EXXRLvcs= 54179 RL # [XX] Exchange RL components
#UseNLCC # [XC] If present, add NLCC contributions to the charge density
Chimod= "hartree" # [X] IP/Hartree/ALDA/LRC/PF/BSfxc
XfnQPdb= "E < ./ndb.QP" # [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_Z= ( 1.000000 , 0.000000 ) # [EXTQP Xd] Z factor (c/v)
XfnQP_Wv_E= 0.000000 eV # [EXTQP Xd] W Energy reference (valence)
% XfnQP_Wv
0.00 | 0.00 | 0.00 | # [EXTQP Xd] W parameters (valence) eV| 1|eV^-1
%
XfnQP_Wv_dos= 0.000000 eV # [EXTQP Xd] W dos pre-factor (valence)
XfnQP_Wc_E= 0.000000 eV # [EXTQP Xd] W Energy reference (conduction)
% XfnQP_Wc
0.00 | 0.00 | 0.00 | # [EXTQP Xd] W parameters (conduction) eV| 1 |eV^-1
%
XfnQP_Wc_dos= 0.000000 eV # [EXTQP Xd] W dos pre-factor (conduction)
% BndsRnXp
1 | 50 | # [Xp] Polarization function bands
%
NGsBlkXp= 10 Ry # [Xp] Response block size
% LongDrXp
1.000000 | 1.000000 | 0.000000 | # [Xp] [cc] Electric Field
%
PPAPntXp= 27.21138 eV # [Xp] PPA imaginary energy
GfnQPdb= "E < ./ndb.QP" # [EXTQP G] Database
GfnQP_N= 1 # [EXTQP G] Interpolation neighbours
% GfnQP_E
0.000000 | 1.000000 | 1.000000 | # [EXTQP G] E parameters (c/v) eV|adim|adim
%
GfnQP_Z= ( 1.000000 , 0.000000 ) # [EXTQP G] Z factor (c/v)
GfnQP_Wv_E= 0.000000 eV # [EXTQP G] W Energy reference (valence)
% GfnQP_Wv
0.00 | 0.00 | 0.00 | # [EXTQP G] W parameters (valence) eV| 1|eV^-1
%
GfnQP_Wv_dos= 0.000000 eV # [EXTQP G] W dos pre-factor (valence)
GfnQP_Wc_E= 0.000000 eV # [EXTQP G] W Energy reference (conduction)
% GfnQP_Wc
0.00 | 0.00 | 0.00 | # [EXTQP G] W parameters (conduction) eV| 1 |eV^-1
%
GfnQP_Wc_dos= 0.000000 eV # [EXTQP G] W dos pre-factor (conduction)
% GbndRnge
1 | 200 | # [GW] G[W] bands range
%
GDamping= 0.10000 eV # [GW] G[W] damping
dScStep= 0.10000 eV # [GW] Energy step to evaluate Z factors
GTermKind= "none" # [GW] GW terminator ("none","BG" Bruneval-Gonze)
GTermEn= 40.81708 eV # [GW] GW terminator energy (only for kind="BG")
DysSolver= "n" # [GW] Dyson Equation solver ("n","s","g")
#NewtDchk # [GW] Test dSc/dw convergence
#ExtendOut # [GW] Print all variables in the output file
#OnMassShell # [F GW] On mass shell approximation
%QPkrange # [GW] QP generalized Kpoint/Band indices
1| 100| 1|15|
%
%QPerange # [GW] QP generalized Kpoint/Energy indices
1| 1| 0.0|-1.0|
%
```

my BSE input file is

Code: Select all

```
optics # [R OPT] Optics
bss # [R BSS] Bethe Salpeter Equation solver
ppa # [R Xp] Plasmon Pole Approximation
bse # [R BSE] Bethe Salpeter Equation.
bsk # [R BSK] Bethe Salpeter Equation kernel
em1d # [R Xd] Dynamical Inverse Dielectric Matrix
Chimod= "Hartree" # [X] IP/Hartree/ALDA/LRC/PF/BSfxc
BSEmod= "retarded" # [BSE] resonant/retarded/coupling
BSKmod= "SEX" # [BSE] IP/Hartree/HF/ALDA/SEX
BSSmod= "d" # [BSS] (h)aydock/(d)iagonalization/(i)nversion/(t)ddft
BSENGexx= 54179 RL # [BSK] Exchange components
BSENGBlk= 9 Ry # [BSK] Screened interaction block size
#WehCpl # [BSK] eh interaction included also in coupling
KfnQPdb= "E < ndb.QP" # [EXTQP BSK BSS] Database
KfnQP_N= 1 # [EXTQP BSK BSS] Interpolation neighbours
% KfnQP_E
0.000000 | 1.000000 | 1.000000 | # [EXTQP BSK BSS] E parameters (c/v) eV|adim|adim
%
KfnQP_Z= ( 1.000000 , 0.000000 ) # [EXTQP BSK BSS] Z factor (c/v)
KfnQP_Wv_E= 0.000000 eV # [EXTQP BSK BSS] W Energy reference (valence)
% KfnQP_Wv
0.00 | 0.00 | 0.00 | # [EXTQP BSK BSS] W parameters (valence) eV| 1|eV^-1
%
KfnQP_Wv_dos= 0.000000 eV # [EXTQP BSK BSS] W dos pre-factor (valence)
KfnQP_Wc_E= 0.000000 eV # [EXTQP BSK BSS] W Energy reference (conduction)
% KfnQP_Wc
0.00 | 0.00 | 0.00 | # [EXTQP BSK BSS] W parameters (conduction) eV| 1 |eV^-1
%
KfnQP_Wc_dos= 0.000000 eV # [EXTQP BSK BSS] W dos pre-factor (conduction)
% BEnRange
0.00000 | 10.00000 | eV # [BSS] Energy range
%
% BDmRange
0.10000 | 0.10000 | eV # [BSS] Damping range
%
BEnSteps= 5000 # [BSS] Energy steps
% BLongDir
1.000000 | 1.000000 | 0.000000 | # [BSS] [cc] Electric Field
%
% BSEBands
1 | 200 | # [BSK] Bands 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_Z= ( 1.000000 , 0.000000 ) # [EXTQP Xd] Z factor (c/v)
XfnQP_Wv_E= 0.000000 eV # [EXTQP Xd] W Energy reference (valence)
% XfnQP_Wv
0.00 | 0.00 | 0.00 | # [EXTQP Xd] W parameters (valence) eV| 1|eV^-1
%
XfnQP_Wv_dos= 0.000000 eV # [EXTQP Xd] W dos pre-factor (valence)
XfnQP_Wc_E= 0.000000 eV # [EXTQP Xd] W Energy reference (conduction)
% XfnQP_Wc
0.00 | 0.00 | 0.00 | # [EXTQP Xd] W parameters (conduction) eV| 1 |eV^-1
%
XfnQP_Wc_dos= 0.000000 eV # [EXTQP Xd] W dos pre-factor (conduction)
% BndsRnXp
1 | 50 | # [Xp] Polarization function bands
%
NGsBlkXp= 10 Ry # [Xp] Response block size
% LongDrXp
1.000000 | 1.000000 | 0.000000 | # [Xp] [cc] Electric Field
%
PPAPntXp= 27.21138 eV # [Xp] PPA imaginary energy
```

Code: Select all

```
[05.01] Transition Groups build-up
==================================
[WARNING] Null BSE kernel block dimension(s) found.
[BSK] Transition groups (total) 14
```

Code: Select all

```
BSK|Identifier : 5306
*ERR* |Dimension : 75
|Bands : 1 200
|Exchange [res]:yes
|Correlation [res]:yes
|Kernel`s coupling :no
|Exchange [cpl]:no
|Correlation [cpl]:no
|W interaction is bare :no
|ALDA kernel in R-space :no
|RL vectors [exchange]: 9531
*ERR* |RL vectors [correlation]: 103
```

Thanks for your assistance!

Chris