Bethe salpether diago/inversion output

You can post here problems arising when using the last release of Yambo. Issues as parallelization strategy, performance issues and other technical aspects realted to the new release.

Moderators: Davide Sangalli, Daniele Varsano, andrea.ferretti, andrea marini, Conor Hogan, myrta gruning

Post Reply
User avatar
wachr
Posts: 32
Joined: Wed Sep 24, 2014 4:43 pm

Bethe salpether diago/inversion output

Post by wachr » Tue Feb 18, 2020 10:15 am

Dear all,

during a BSE calculation, where I needed the oscillator strengths, I ran a calculation using the diagonalization solver (and the inversion solver for a calculation on a double grid). BTW, in this system (2D heterostack), there is trouble converging the spectrum with the Haydock solver (no convergence after 1000 iterations; spectrum looks a bit too peaky) - but that's not the problem, here.

Looking at the report files, I was surprised to see that o.eps_q1_diago_bse and o.eel_q1_diago_bse report basically vacuum screening. However, looking at o.alpha_q1_diago_bse, the content appears fine. Further, exciton sorting using ypp worked. And the haydock spectrum o.eps_q1_haydock_bse looks ok - besides the convergence issues. (not appended here, as it's available only for other calculations of the same system, but different k-grid)

Thus, I guess that this is a pure problem on calculating or printing epsilon from the diagonalized excitonic Hamiltonian. Don't know if this is already fixed or not, but I found it useful to report this issue. This has not yet happened in yambo 4.2, where I performed a similar calculation.

Best!
Christian

Output of o.alpha_q1_diago_bse looks reasonable:

Code: Select all

#  __  __   ________   ___ __ __    _______   ______
# /_/\/_/\ /_______/\ /__//_//_/\ /_______/\ /_____/\
# \ \ \ \ \\::: _  \ \\::\| \| \ \\::: _  \ \\:::_ \ \
#  \:\_\ \ \\::(_)  \ \\:.      \ \\::(_)  \/_\:\ \ \ \
#   \::::_\/ \:: __  \ \\:.\-/\  \ \\::  _  \ \\:\ \ \ \
#     \::\ \  \:.\ \  \ \\. \  \  \ \\::(_)  \ \\:\_\ \ \
#      \__\/   \__\/\__\/ \__\/ \__\/ \_______\/ \_____\/
#
#
# GPL Version 4.4.0 Revision 148. (Based on r.16920 h.961a8d
#                        MPI Build
#                http://www.yambo-code.org
#
# Polarizability ( -<<X>> ) [length @ Q(1) [q->0 direction]0.7071E-5 0.7071E-5  0.000
#
#
# - Energies      are Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
# - Wavefunctions are Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
#
# - The Green`s function is Retarded -
# - Using the Length Gauge -
# - [r,Vnl] *is* included -
#
#   BSK|Identifier              :6579
#      |Dimension               :17424
#      |Bands                   :129 - 150
#      |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]:63131
#      |RL vectors [correlation]:357
#      |E/h energy range    [ev]:-1.000000 - -1.000000
#      |Coupling range     [o/o]: 100.0000 -  100.0000
#    W |Interaction is diagonal : no
#      |Matrix size             :357
#      |Bands                   :1 - 300
#      |e/h energy range    [ev]:-1.000000 - -1.000000
#      |Poles              [o/o]: 100.0000
#      |RL vectors in the sum   :108857
#      |[r,Vnl] included        : yes
#      |Field direction         :0.7071E-5 0.7071E-5  0.000000
#      |Coulomb Cutoff          :box z
#      |xc-Kernel               :none
#   RIM|RL components      [col]:1
#      |Random points      [col]:3000000
#
#    Alpha is in a.u. of length
#
#    E/ev[1]      ALPHA-Im[2]  ALPHA-Re[3]  ALPHAo-Im[4] ALPHAo-Re[5]
#
     0.00000      0.00000     13.97741      0.00000      9.27556
   0.2000E-1    0.6433E-2     13.98       0.1480E-2     9.276
   0.4000E-1    0.1289E-1     13.99       0.2961E-2     9.278
   0.6000E-1    0.1940E-1     14.00       0.4445E-2     9.281
   0.8000E-1    0.2598E-1     14.02       0.5934E-2     9.285
   0.1000       0.3266E-1     14.04       0.7428E-2     9.290
   0.1200       0.3947E-1     14.07       0.8930E-2     9.297
   0.1400       0.4645E-1     14.11       0.1044E-1     9.305
   0.1600       0.5361E-1     14.15       0.1196E-1     9.314
   0.1800       0.6100E-1     14.19       0.1349E-1     9.324
     0.20000      0.06865     14.24253      0.01504      9.33520
     0.22000      0.07662     14.30048      0.01660      9.34784
     0.24000      0.08493     14.36492      0.01818      9.36175
     0.26000      0.09366     14.43614      0.01977      9.37692
     0.28000      0.10286     14.51450      0.02139      9.39337
     0.30000      0.11260     14.60041      0.02303      9.41113
     0.32000      0.12296     14.69430      0.02469      9.43021
     0.34000      0.13404     14.79672      0.02638      9.45062
     0.36000      0.14596     14.90830      0.02810      9.47240
     0.38000      0.15885     15.02971      0.02985      9.49556
     0.40000      0.17287     15.16180      0.03163      9.52014
     0.42000      0.18821     15.30553      0.03345      9.54615
     0.44000      0.20513     15.46204      0.03530      9.57363
     0.46000      0.22392     15.63268      0.03719      9.60261
     0.48000      0.24494     15.81903      0.03913      9.63312
     0.50000      0.26869     16.02302      0.04112      9.66519
     0.52000      0.29575     16.24700      0.04315      9.69888
     0.54000      0.32694     16.49384      0.04524      9.73421
     0.56000      0.36330     16.76711      0.04739      9.77124
     0.58000      0.40627     17.07131      0.04960      9.81000
     0.60000      0.45780     17.41215      0.05187      9.85056
     0.62000      0.52068     17.79714      0.05422      9.89296
     0.64000      0.59895     18.23618      0.05664      9.93726
     0.66000      0.69865     18.74274      0.05914      9.98353
     0.68000      0.82921     19.33555      0.06172     10.03183
     0.70000      1.00592     20.04149      0.06441     10.08224
     0.72000      1.25497     20.90035      0.06719     10.13482
     0.74000      1.62423     21.97324      0.07008     10.18967
     0.76000      2.20849     23.35738      0.07308     10.24688
     0.78000      3.21535     25.21012      0.07622     10.30653
     0.80000      5.16036     27.76701      0.07948     10.36874
     0.82000      9.50670     31.13504      0.08290     10.43362
     0.84000     20.19430     32.72797      0.08647     10.50129
     0.86000     32.84424     17.38252      0.09022     10.57188
     0.88000     20.36116      2.18957      0.09416     10.64554
     0.90000      9.96500      4.04792      0.09831     10.72242
     0.92000      6.00606      7.85997      0.10268     10.80270
     0.94000      4.70760     11.12936      0.10730     10.88657
     0.96000      5.03218     14.01609      0.11220     10.97423
     0.98000      7.64228     16.16470      0.11739     11.06591
     1.00000     12.03096     13.24280      0.12293     11.16186
     1.02000      8.58827      8.25144      0.12883     11.26238
     1.04000      4.69125      9.23851      0.13516     11.36777
     1.06000      3.09079     11.15582      0.14195     11.47837
     1.08000      2.46498     12.79362      0.14928     11.59459
     1.10000      2.14178     14.28227      0.15720     11.71687
     1.12000      2.11341     15.80468      0.16581     11.84572
     1.14000      2.39999     17.41664      0.17521     11.98172
     1.16000      3.18511     19.24373      0.18552     12.12553
     1.18000      5.14078     21.28971      0.19690     12.27795
[...]
# Timing   [Min/Max/Average]: 11h-15m-13s/11h-15m-17s/11h-15m-16s
#
# .-Input file : 04_BSE_11_diag.in
# | optics                         # [R OPT] Optics
# | bse                            # [R BSE] Bethe Salpeter Equation.
# | bsk                            # [R BSK] Bethe Salpeter Equation kernel
# | bss                            # [R BSS] Bethe Salpeter Equation solver
# | rim_cut                        # [R RIM CUT] Coulomb potential
# | ElecTemp=  0.02588     eV      # Electronic Temperature
# | FFTGvecs=  60          Ry      # [FFT] Plane-waves
# | BS_CPU= "4.6"                  # [PARALLEL] CPUs for each role
# | BS_ROLEs= "eh.k"               # [PARALLEL] CPUs roles (k,eh,t)
# | RandQpts= 3000000              # [RIM] Number of random q-points in the BZ
# | RandGvec= 1            RL      # [RIM] Coulomb interaction RS components
# | CUTGeo= "box z"                # [CUT] Coulomb Cutoff geometry: box/cylinder/sphere/ws X/Y/Z/XY..
# | % CUTBox
# |   0.00000 |  0.00000 | 60.00000 |        # [CUT] [au] Box sides
# | %
# | CUTRadius= 0.000000            # [CUT] [au] Sphere/Cylinder radius
# | CUTCylLen= 0.000000            # [CUT] [au] Cylinder length
# | CUTwsGvec= 0.000000            # [CUT] WS cutoff: number of G to be modified
# | 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=  60          Ry      # [BSK] Exchange components
# | BSENGBlk=  357         RL      # [BSK] Screened interaction block size
# | #WehCpl                        # [BSK] eh interaction included also in coupling
# | % BEnRange
# |  0.000000 | 5.000000 | eV      # [BSS] Energy range
# | %
# | % BDmRange
# |   0.02500 |  0.02500 | eV      # [BSS] Damping range
# | %
# | BEnSteps= 251                  # [BSS] Energy steps
# | % BLongDir
# | 0.7071E-5 |0.7071E-5 | 0.000    |        # [BSS] [cc] Electric Field
# | %
# | % BSEBands
# |  129 | 150 |                   # [BSK] Bands range
# | %
# | WRbsWF                         # [BSS] Write to disk excitonic the WFs
Output of o.eps_q1_diago_bse looks strange:

Code: Select all

#
#  __  __   ________   ___ __ __    _______   ______
# /_/\/_/\ /_______/\ /__//_//_/\ /_______/\ /_____/\
# \ \ \ \ \\::: _  \ \\::\| \| \ \\::: _  \ \\:::_ \ \
#  \:\_\ \ \\::(_)  \ \\:.      \ \\::(_)  \/_\:\ \ \ \
#   \::::_\/ \:: __  \ \\:.\-/\  \ \\::  _  \ \\:\ \ \ \
#     \::\ \  \:.\ \  \ \\. \  \  \ \\::(_)  \ \\:\_\ \ \
#      \__\/   \__\/\__\/ \__\/ \__\/ \_______\/ \_____\/
#
#
# GPL Version 4.4.0 Revision 148. (Based on r.16920 h.961a8d
#                        MPI Build
#                http://www.yambo-code.org
#
# Absorption @ Q(1) [q->0 direction] :0.7071E-5 0.7071E-5  0.000
#
#
# - Energies      are Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
# - Wavefunctions are Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
#
# - The Green`s function is Retarded -
# - Using the Length Gauge -
# - [r,Vnl] *is* included -
#
#   BSK|Identifier              :6579
#      |Dimension               :17424
#      |Bands                   :129 - 150
#      |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]:63131
#      |RL vectors [correlation]:357
#      |E/h energy range    [ev]:-1.000000 - -1.000000
#      |Coupling range     [o/o]: 100.0000 -  100.0000
#    W |Interaction is diagonal : no
#      |Matrix size             :357
#      |Bands                   :1 - 300
#      |e/h energy range    [ev]:-1.000000 - -1.000000
#      |Poles              [o/o]: 100.0000
#      |RL vectors in the sum   :108857
#      |[r,Vnl] included        : yes
#      |Field direction         :0.7071E-5 0.7071E-5  0.000000
#      |Coulomb Cutoff          :box z
#      |xc-Kernel               :none
#   RIM|RL components      [col]:1
#      |Random points      [col]:3000000
#
#    E/ev[1]      EPS-Im[2]    EPS-Re[3]    EPSo-Im[4]   EPSo-Re[5]
    0.000000     0.000000     1.000001     0.000000     1.000000
   0.200E-01    0.251E-09     1.00        0.578E-10     1.00
   0.400E-01    0.503E-09     1.00        0.116E-09     1.00
   0.600E-01    0.757E-09     1.00        0.174E-09     1.00
   0.800E-01    0.101E-08     1.00        0.232E-09     1.00
   0.100        0.128E-08     1.00        0.290E-09     1.00
   0.120        0.154E-08     1.00        0.349E-09     1.00
   0.140        0.181E-08     1.00        0.408E-09     1.00
   0.160        0.209E-08     1.00        0.467E-09     1.00
   0.180        0.238E-08     1.00        0.527E-09     1.00
   0.200        0.268E-08     1.00        0.587E-09     1.00
   0.220        0.299E-08     1.00        0.648E-09     1.00
   0.240        0.332E-08     1.00        0.710E-09     1.00
   0.260        0.366E-08     1.00        0.772E-09     1.00
   0.280        0.402E-08     1.00        0.835E-09     1.00
   0.300        0.440E-08     1.00        0.899E-09     1.00
   0.320        0.480E-08     1.00        0.964E-09     1.00
   0.3400       0.5234E-8     1.000       0.1030E-8     1.000
   0.3600       0.5699E-8     1.000       0.1097E-8     1.000
   0.3800       0.6202E-8     1.000       0.1165E-8     1.000
   0.4000       0.6750E-8     1.000       0.1235E-8     1.000
   0.4200       0.7349E-8     1.000       0.1306E-8     1.000
   0.4400       0.8009E-8     1.000       0.1378E-8     1.000
   0.4600       0.8743E-8     1.000       0.1452E-8     1.000
   0.4800       0.9564E-8     1.000       0.1528E-8     1.000
   0.5000       0.1049E-7     1.000       0.1605E-8     1.000
   0.5200       0.1155E-7     1.000       0.1685E-8     1.000
   0.5400       0.1277E-7     1.000       0.1767E-8     1.000
   0.5600       0.1419E-7     1.000       0.1850E-8     1.000
   0.5800       0.1586E-7     1.000       0.1937E-8     1.000
   0.6000       0.1787E-7     1.000       0.2025E-8     1.000
   0.6200       0.2033E-7     1.000       0.2117E-8     1.000
   0.6400       0.2339E-7     1.000       0.2211E-8     1.000
   0.6600       0.2728E-7     1.000       0.2309E-8     1.000
   0.6800       0.3238E-7     1.000       0.2410E-8     1.000
   0.7000       0.3928E-7     1.000       0.2515E-8     1.000
   0.7200       0.4900E-7     1.000       0.2623E-8     1.000
   0.7400       0.6342E-7     1.000       0.2736E-8     1.000
   0.7600       0.8623E-7     1.000       0.2854E-8     1.000
   0.7800       0.1255E-6     1.000       0.2976E-8     1.000
   0.8000       0.2015E-6     1.000       0.3103E-8     1.000
   0.8200       0.3712E-6     1.000       0.3237E-8     1.000
   0.8400       0.7885E-6     1.000       0.3376E-8     1.000
   0.8600       0.1282E-5     1.000       0.3523E-8     1.000
   0.8800       0.7950E-6     1.000       0.3677E-8     1.000
   0.9000       0.3891E-6     1.000       0.3838E-8     1.000
   0.9200       0.2345E-6     1.000       0.4009E-8     1.000
   0.9400       0.1838E-6     1.000       0.4190E-8     1.000
   0.9600       0.1965E-6     1.000       0.4381E-8     1.000
   0.9800       0.2984E-6     1.000       0.4584E-8     1.000
    1.000       0.4697E-6     1.000       0.4800E-8     1.000
    1.020       0.3353E-6     1.000       0.5030E-8     1.000
    1.040       0.1832E-6     1.000       0.5277E-8     1.000
    1.060       0.1207E-6     1.000       0.5543E-8     1.000
    1.080       0.9624E-7     1.000       0.5828E-8     1.000
    1.100       0.8363E-7     1.000       0.6138E-8     1.000
[...]
# Timing   [Min/Max/Average]: 11h-15m-13s/11h-15m-17s/11h-15m-16s
#
# .-Input file : 04_BSE_11_diag.in
# | optics                         # [R OPT] Optics
# | bse                            # [R BSE] Bethe Salpeter Equation.
# | bsk                            # [R BSK] Bethe Salpeter Equation kernel
# | bss                            # [R BSS] Bethe Salpeter Equation solver
# | rim_cut                        # [R RIM CUT] Coulomb potential
# | ElecTemp=  0.02588     eV      # Electronic Temperature
# | FFTGvecs=  60          Ry      # [FFT] Plane-waves
# | BS_CPU= "4.6"                  # [PARALLEL] CPUs for each role
# | BS_ROLEs= "eh.k"               # [PARALLEL] CPUs roles (k,eh,t)
# | RandQpts= 3000000              # [RIM] Number of random q-points in the BZ
# | RandGvec= 1            RL      # [RIM] Coulomb interaction RS components
# | CUTGeo= "box z"                # [CUT] Coulomb Cutoff geometry: box/cylinder/sphere/ws X/Y/Z/XY..
# | % CUTBox
# |   0.00000 |  0.00000 | 60.00000 |        # [CUT] [au] Box sides
# | %
# | CUTRadius= 0.000000            # [CUT] [au] Sphere/Cylinder radius
# | CUTCylLen= 0.000000            # [CUT] [au] Cylinder length
# | CUTwsGvec= 0.000000            # [CUT] WS cutoff: number of G to be modified
# | 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=  60          Ry      # [BSK] Exchange components
# | BSENGBlk=  357         RL      # [BSK] Screened interaction block size
# | #WehCpl                        # [BSK] eh interaction included also in coupling
# | % BEnRange
# |  0.000000 | 5.000000 | eV      # [BSS] Energy range
# | %
# | % BDmRange
# |   0.02500 |  0.02500 | eV      # [BSS] Damping range
# | %
# | BEnSteps= 251                  # [BSS] Energy steps
# | % BLongDir
# | 0.7071E-5 |0.7071E-5 | 0.000    |        # [BSS] [cc] Electric Field
# | %
# | % BSEBands
# |  129 | 150 |                   # [BSK] Bands range
# | %
# | WRbsWF                         # [BSS] Write to disk excitonic the WFs
The same for o.eel_q1_diago_bse:

Code: Select all

#
#  __  __   ________   ___ __ __    _______   ______
# /_/\/_/\ /_______/\ /__//_//_/\ /_______/\ /_____/\
# \ \ \ \ \\::: _  \ \\::\| \| \ \\::: _  \ \\:::_ \ \
#  \:\_\ \ \\::(_)  \ \\:.      \ \\::(_)  \/_\:\ \ \ \
#   \::::_\/ \:: __  \ \\:.\-/\  \ \\::  _  \ \\:\ \ \ \
#     \::\ \  \:.\ \  \ \\. \  \  \ \\::(_)  \ \\:\_\ \ \
#      \__\/   \__\/\__\/ \__\/ \__\/ \_______\/ \_____\/
#
#
# GPL Version 4.4.0 Revision 148. (Based on r.16920 h.961a8d
#                        MPI Build
#                http://www.yambo-code.org
#
# EELS @ Q(1)  [q->0 direction]:0.7071E-5 0.7071E-5  0.000
#
#
# - Energies      are Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
# - Wavefunctions are Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
#
# - The Green`s function is Retarded -
# - Using the Length Gauge -
# - [r,Vnl] *is* included -
#
#   BSK|Identifier              :6579
#      |Dimension               :17424
#      |Bands                   :129 - 150
#      |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]:63131
#      |RL vectors [correlation]:357
#      |E/h energy range    [ev]:-1.000000 - -1.000000
#      |Coupling range     [o/o]: 100.0000 -  100.0000
#    W |Interaction is diagonal : no
#      |Matrix size             :357
#      |Bands                   :1 - 300
#      |e/h energy range    [ev]:-1.000000 - -1.000000
#      |Poles              [o/o]: 100.0000
#      |RL vectors in the sum   :108857
#      |[r,Vnl] included        : yes
#      |Field direction         :0.7071E-5 0.7071E-5  0.000000
#      |Coulomb Cutoff          :box z
#      |xc-Kernel               :none
#   RIM|RL components      [col]:1
#      |Random points      [col]:3000000
#
#    E/ev[1]      EEL-Im[2]    EEL-Re[3]    EELo-Im[4]   EELo-Re[5]
#
    0.000000    -0.000000    -0.999999    -0.000000    -1.000000
   0.200E-01    0.251E-09    -1.00        0.578E-10    -1.00
   0.400E-01    0.503E-09    -1.00        0.116E-09    -1.00
   0.600E-01    0.757E-09    -1.00        0.174E-09    -1.00
   0.800E-01    0.101E-08    -1.00        0.232E-09    -1.00
   0.100        0.128E-08    -1.00        0.290E-09    -1.00
   0.120        0.154E-08    -1.00        0.349E-09    -1.00
   0.140        0.181E-08    -1.00        0.408E-09    -1.00
   0.160        0.209E-08    -1.00        0.467E-09    -1.00
   0.180        0.238E-08    -1.00        0.527E-09    -1.00
   0.200        0.268E-08    -1.00        0.587E-09    -1.00
   0.220        0.299E-08    -1.00        0.648E-09    -1.00
   0.240        0.332E-08    -1.00        0.710E-09    -1.00
   0.260        0.366E-08    -1.00        0.772E-09    -1.00
   0.280        0.402E-08    -1.00        0.835E-09    -1.00
   0.300        0.440E-08    -1.00        0.899E-09    -1.00
   0.320        0.480E-08    -1.00        0.964E-09    -1.00
   0.3400       0.5234E-8    -1.000       0.1030E-8    -1.000
   0.3600       0.5699E-8    -1.000       0.1097E-8    -1.000
   0.3800       0.6202E-8    -1.000       0.1165E-8    -1.000
   0.4000       0.6750E-8    -1.000       0.1235E-8    -1.000
   0.4200       0.7349E-8    -1.000       0.1306E-8    -1.000
   0.4400       0.8009E-8    -1.000       0.1378E-8    -1.000
   0.4600       0.8743E-8    -1.000       0.1452E-8    -1.000
   0.4800       0.9564E-8    -1.000       0.1528E-8    -1.000
   0.5000       0.1049E-7    -1.000       0.1605E-8    -1.000
   0.5200       0.1155E-7    -1.000       0.1685E-8    -1.000
   0.5400       0.1277E-7    -1.000       0.1767E-8    -1.000
   0.5600       0.1419E-7    -1.000       0.1850E-8    -1.000
   0.5800       0.1586E-7    -1.000       0.1937E-8    -1.000
   0.6000       0.1787E-7    -1.000       0.2025E-8    -1.000
   0.6200       0.2033E-7    -1.000       0.2117E-8    -1.000
   0.6400       0.2339E-7    -1.000       0.2211E-8    -1.000
   0.6600       0.2728E-7    -1.000       0.2309E-8    -1.000
   0.6800       0.3238E-7    -1.000       0.2410E-8    -1.000
   0.7000       0.3928E-7    -1.000       0.2515E-8    -1.000
   0.7200       0.4900E-7    -1.000       0.2623E-8    -1.000
   0.7400       0.6342E-7    -1.000       0.2736E-8    -1.000
   0.7600       0.8623E-7    -1.000       0.2854E-8    -1.000
   0.7800       0.1255E-6    -1.000       0.2976E-8    -1.000
   0.8000       0.2015E-6    -1.000       0.3103E-8    -1.000
   0.8200       0.3712E-6    -1.000       0.3237E-8    -1.000
   0.8400       0.7885E-6    -1.000       0.3376E-8    -1.000
   0.8600       0.1282E-5    -1.000       0.3523E-8    -1.000
   0.8800       0.7950E-6    -1.000       0.3677E-8    -1.000
   0.9000       0.3891E-6    -1.000       0.3838E-8    -1.000
   0.9200       0.2345E-6    -1.000       0.4009E-8    -1.000
   0.9400       0.1838E-6    -1.000       0.4190E-8    -1.000
   0.9600       0.1965E-6    -1.000       0.4381E-8    -1.000
   0.9800       0.2984E-6    -1.000       0.4584E-8    -1.000
    1.000       0.4697E-6    -1.000       0.4800E-8    -1.000
    1.020       0.3353E-6    -1.000       0.5030E-8    -1.000
    1.040       0.1832E-6    -1.000       0.5277E-8    -1.000
    1.060       0.1207E-6    -1.000       0.5543E-8    -1.000
    1.080       0.9624E-7    -1.000       0.5828E-8    -1.000
    1.100       0.8363E-7    -1.000       0.6138E-8    -1.000
# Timing   [Min/Max/Average]: 11h-15m-13s/11h-15m-17s/11h-15m-16s
#
# .-Input file : 04_BSE_11_diag.in
# | optics                         # [R OPT] Optics
# | bse                            # [R BSE] Bethe Salpeter Equation.
# | bsk                            # [R BSK] Bethe Salpeter Equation kernel
# | bss                            # [R BSS] Bethe Salpeter Equation solver
# | rim_cut                        # [R RIM CUT] Coulomb potential
# | ElecTemp=  0.02588     eV      # Electronic Temperature
# | FFTGvecs=  60          Ry      # [FFT] Plane-waves
# | BS_CPU= "4.6"                  # [PARALLEL] CPUs for each role
# | BS_ROLEs= "eh.k"               # [PARALLEL] CPUs roles (k,eh,t)
# | RandQpts= 3000000              # [RIM] Number of random q-points in the BZ
# | RandGvec= 1            RL      # [RIM] Coulomb interaction RS components
# | CUTGeo= "box z"                # [CUT] Coulomb Cutoff geometry: box/cylinder/sphere/ws X/Y/Z/XY..
# | % CUTBox
# |   0.00000 |  0.00000 | 60.00000 |        # [CUT] [au] Box sides
# | %
# | CUTRadius= 0.000000            # [CUT] [au] Sphere/Cylinder radius
# | CUTCylLen= 0.000000            # [CUT] [au] Cylinder length
# | CUTwsGvec= 0.000000            # [CUT] WS cutoff: number of G to be modified
# | 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=  60          Ry      # [BSK] Exchange components
# | BSENGBlk=  357         RL      # [BSK] Screened interaction block size
# | #WehCpl                        # [BSK] eh interaction included also in coupling
# | % BEnRange
# |  0.000000 | 5.000000 | eV      # [BSS] Energy range
# | %
# | % BDmRange
# |   0.02500 |  0.02500 | eV      # [BSS] Damping range
# | %
# | BEnSteps= 251                  # [BSS] Energy steps
# | % BLongDir
# | 0.7071E-5 |0.7071E-5 | 0.000    |        # [BSS] [cc] Electric Field
# | %
# | % BSEBands
# |  129 | 150 |                   # [BSK] Bands range
# | %
# | WRbsWF                         # [BSS] Write to disk excitonic the WFs
Christian Wagner
Institute of Physics
Chemnitz University of Technology, Germany

User avatar
Davide Sangalli
Posts: 345
Joined: Tue May 29, 2012 4:49 pm
Location: Via Salaria Km 29.3, CP 10, 00016, Monterotondo Stazione, Italy
Contact:

Re: Bethe salpether diago/inversion output

Post by Davide Sangalli » Tue Feb 18, 2020 12:11 pm

Dear Christian,
I guess you are using some Coulomb cutoff technique.

It is correct that the epsilon, which is defined as the average over the unit cell of your 2D material, is basically the one of vacuum. Indeed there is a lot of vacuum in the unit cell and, using Coulomb cutoff is somehow equivalent to have a unit cell which is infinite. It is also correct that the alpha is instead finite, since the latter is independent on the volume used in the simulation.
A useful reference is this one: Physical Review B 88, 245309 (2013)

What you can do for 2D systems, if you need so, is to define an effective dielectric tensor starting from alpha.
See for example eq 1 here:
https://arxiv.org/pdf/1912.01888.pdf

Hope it helps.
Best,
D.
Davide Sangalli, PhD
CNR-ISM, Division of Ultrafast Processes in Materials (FLASHit) and MaX Centre
http://www.ism.cnr.it/en/davide-sangalli-cv/
http://www.max-centre.eu/

User avatar
wachr
Posts: 32
Joined: Wed Sep 24, 2014 4:43 pm

Re: Bethe salpether diago/inversion output

Post by wachr » Tue Feb 18, 2020 1:06 pm

Dear Davide,

thanks a lot for your answer. So now I understand the output correctly - this behaviour somehow changed during the versions of yambo, where the cell-averaged epsilon / eels was printed. This may also clarify, why the Haydock solver is struggling.

With this answer, I can work! Thank you!

Best,
Christian
Christian Wagner
Institute of Physics
Chemnitz University of Technology, Germany

Post Reply