I did a series BSE calculations on graphane system, and came to several confusions. Would you please give me a hand about these questions ?
1, I employed Coulomn cutoff scheme to remove the long-range image interactions, however, i found the resulted absorption spectrum showed a quite different shape, as attached. It seems this result cannot satisfy f-sum rule since the oscillation amplitude isnot damping in the high energy . The setup of this calculation is as follows:
a, yambo -b -c
Code: Select all
| em1s # [R Xs] Static Inverse Dielectric Matrix
| rim_cut # [R RIM CUT] Coulomb interaction
| FFTGvecs= 4697 RL # [FFT] Plane-waves
| RandQpts= 500000 # [RIM] Number of random q-points in the BZ
| RandGvec= 13 RL # [RIM] Coulomb interaction RS components
| CUTGeo= "box z" # [CUT] Coulomb Cutoff geometry: box/cylinder/sphere
| % CUTBox
| 0.00000 | 0.00000 | 10.00000 | # [CUT] [au] Box sides
| %
| CUTRadius= 0.000000 # [CUT] [au] Sphere/Cylinder radius
| CUTCylLen= 0.000000 # [CUT] [au] Cylinder length
| % XfnQP_E
| 2.000000 | 1.000000 | 1.000000 | # [EXTQP Xd] E parameters (c/v)
| %
| % QpntsRXs
| 1 | 102 | # [Xs] Transferred momenta
| %
| % BndsRnXs
| 1 | 100 | # [Xs] Polarization function bands
| %
| NGsBlkXs= 63 RL # [Xs] Response block size
| % LongDrXs
| 0.1000E-4 | 0.000 | 0.000 | # [Xs] [cc] Electric Field
| %
Code: Select all
| optics # [R OPT] Optics
| bse # [R BSK] Bethe Salpeter Equation.
| bss # [R BSS] Bethe Salpeter Equation solver
| rim_cut # [R RIM CUT] Coulomb interaction
| RandQpts= 500000 # [RIM] Number of random q-points in the BZ
| RandGvec= 13 RL # [RIM] Coulomb interaction RS components
| CUTGeo= "box z" # [CUT] Coulomb Cutoff geometry: box/cylinder/sphere
| % CUTBox
| 0.00000 | 0.00000 | 10.00000 | # [CUT] [au] Box sides
| %
| CUTRadius= 0.000000 # [CUT] [au] Sphere/Cylinder radius
| CUTCylLen= 0.000000 # [CUT] [au] Cylinder length
| % KfnQP_E
| 2.000000 | 1.000000 | 1.000000 | # [EXTQP BSK BSS] E parameters (c/v)
| %
| BSresKmod= "xc" # [BSK] Resonant Kernel mode. (`x`;`c`;`d`)
| BScplKmod= "none" # [BSK] Coupling Kernel mode. (`x`;`c`;`d`;`u`)
| % BSEBands
| 3 | 24 | # [BSK] Bands range
| %
| BSENGBlk= 63 RL # [BSK] Screened interaction block size
| BSENGexx= 4697 RL # [BSK] Exchange components
| BSSmod= "h" # [BSS] Solvers `h/d/i/t`
| % BEnRange
| 0.00000 | 15.00000 | eV # [BSS] Energy range
| %
| % BDmRange
| 0.10000 | 0.10000 | eV # [BSS] Damping range
| %
| BEnSteps= 400 # [BSS] Energy steps
| % BLongDir
| 0.1000E-4 | 0.000 | 0.000 | # [BSS] [cc] Electric Field
| %
The spectra also shows a bit difference from that in PRL 104 226804.
2, When i trigger on both coulomb cutoff and BScplKmod= "xc", the results show NaN , and the file is attached.
I tried several different combinations between BSENGBlk and BSEBands, and didnot solve this failure.
Thank you!
Best,
Haiping