# Calculating excitonic optical properties with BSE level in VASP

I have been working on 2D material systems and their heterostructures. While calculating BSE excitonic optical properties in VASP, I encountered that the 2D material property is well matched with existing literature. However, while calculating for the vdW heterostructures, the optical properties data show the transmission is all 1 and other values are zero (dielectric functions, absorbance, and others). Also, the vasprun.xml file shows zero value in optical transition. What could be the possible reason for that? Do I need to change any process in VASP for calculating the heterostructure? Please suggest.

I have got the QP energies as bellow:

QP shifts <psi_nk| G(iteration)W_0 |psi_nk>: iteration 1
for sc-GW calculations column KS-energies equals QP-energies in previous step
and V_xc(KS)=  KS-energies - (<T + V_ion + V_H > + <T+V_H+V_ion>^1  + <V_x>^1)

k-point   1 :       0.0000    0.0000    0.0000
band No.  KS-energies  QP-energies   sigma(KS)   V_xc(KS)     V^pw_x(r,r')   Z            occupation Imag(sigma)

1     -62.8363     -65.2242     -27.0299     -22.8607     -38.6210       0.5728       2.0000       1.8799
2     -37.0378     -38.0953     -23.7962     -22.0873     -32.4098       0.6188       2.0000       1.3720
3     -36.8254     -37.7533     -23.7562     -22.2636     -32.4047       0.6217       2.0000       1.2829
4     -36.8254     -37.7533     -23.7562     -22.2636     -32.4047       0.6217       2.0000       1.2829
5     -16.4670     -17.7385     -13.5822     -11.9121     -19.5849       0.7613       2.0000       2.1266
6     -15.6562     -16.3879     -13.5268     -12.5216     -19.9985       0.7280       2.0000       2.1676
7     -14.6190     -15.3365     -13.5135     -12.5264     -19.4682       0.7269       2.0000       1.8251
8      -7.5844      -8.2602     -12.2364     -11.3903     -15.6500       0.7987       2.0000       0.7739

k-point   2 :       0.2000   -0.0000    0.0000
band No.  KS-energies  QP-energies   sigma(KS)   V_xc(KS)     V^pw_x(r,r')   Z            occupation Imag(sigma)

1     -62.8288     -65.2243     -27.0334     -22.8670     -38.6189       0.5750       2.0000       1.8787
2     -37.0209     -38.0689     -23.7988     -22.1081     -32.4182       0.6198       2.0000       1.3521
3     -36.9096     -37.8571     -23.7110     -22.1775     -32.4160       0.6179       2.0000       1.3292
4     -36.8449     -37.7752     -23.7444     -22.2454     -32.4114       0.6206       2.0000       1.2895
5     -15.8923     -17.1215     -13.5842     -11.9698     -19.3782       0.7614       2.0000       1.9473
6     -15.1227     -15.8192     -13.9738     -12.9963     -20.4355       0.7125       2.0000       2.0006
7     -14.2436     -14.9473     -13.2395     -12.2898     -18.9058       0.7410       2.0000       1.6993
8      -7.0102      -7.6028     -12.4362     -11.6909     -15.6074       0.7952       2.0000       0.6547

k-point   3 :       0.4000   -0.0000    0.0000
band No.  KS-energies  QP-energies   sigma(KS)   V_xc(KS)     V^pw_x(r,r')   Z            occupation Imag(sigma)

1     -62.8168     -65.2231     -27.0387     -22.8770     -38.6154       0.5782       2.0000       1.8769
2     -37.0435     -38.0218     -23.6389     -22.0440     -32.4407       0.6134       2.0000       1.4071
3     -36.9933     -38.0239     -23.8017     -22.1419     -32.4220       0.6210       2.0000       1.3158
4     -36.8763     -37.8098     -23.7246     -22.2162     -32.4226       0.6189       2.0000       1.3004
5     -14.3883     -15.5066     -13.6583     -12.1876     -18.8463       0.7604       2.0000       1.5329
6     -14.2828     -14.9110     -14.9380     -14.0302     -21.4574       0.6921       2.0000       1.7817
7     -13.0774     -13.7090     -12.7315     -11.9068     -17.6882       0.7659       2.0000       1.3788
8     -10.0008     -11.0448     -13.3380     -12.0196     -17.0548       0.7919       2.0000       0.8065

k-point   4 :       0.2000    0.2000    0.0000
band No.  KS-energies  QP-energies   sigma(KS)   V_xc(KS)     V^pw_x(r,r')   Z            occupation Imag(sigma)

1     -62.8191     -65.2176     -27.0379     -22.8751     -38.6162       0.5762       2.0000       1.8771
2     -36.9993     -38.0186     -23.7720     -22.1251     -32.4256       0.6189       2.0000       1.3420
3     -36.9959     -37.9767     -23.6933     -22.1010     -32.4282       0.6159       2.0000       1.3599
4     -36.8922     -37.8292     -23.7160     -22.1990     -32.4217       0.6177       2.0000       1.3101
5     -14.8197     -15.9825     -13.6225     -12.1025     -18.9895       0.7650       2.0000       1.6477
6     -14.4356     -15.0793     -14.7893     -13.8613     -21.3122       0.6936       2.0000       1.8217
7     -13.4211     -14.0841     -12.7561     -11.8835     -17.8605       0.7598       2.0000       1.4611
8      -8.7007      -9.6114     -13.4932     -12.3510     -16.7722       0.7973       2.0000       0.6236

k-point   5 :       0.4000    0.2000    0.0000
band No.  KS-energies  QP-energies   sigma(KS)   V_xc(KS)     V^pw_x(r,r')   Z            occupation Imag(sigma)

1     -62.8131     -65.2275     -27.0407     -22.8801     -38.6147       0.5803       2.0000       1.8762
2     -37.0386     -38.0163     -23.6419     -22.0501     -32.4351       0.6142       2.0000       1.4009
3     -36.9848     -38.0120     -23.8029     -22.1524     -32.4247       0.6224       2.0000       1.3056
4     -36.9332     -37.8765     -23.6914     -22.1585     -32.4328       0.6154       2.0000       1.3308
5     -14.0571     -14.6685     -15.1023     -14.2224     -21.5755       0.6949       2.0000       1.7189
6     -13.6048     -14.6591     -13.7255     -12.3556     -18.5442       0.7697       2.0000       1.3413
7     -12.4684     -13.0429     -12.8139     -12.0695     -17.5470       0.7717       2.0000       1.2372
8     -10.4955     -11.6021     -13.4402     -12.0323     -17.4385       0.7861       2.0000       0.8922

and the optical properties are:
The optical spectra including excitonic effects are calculated on a grid of 1000 energy points up to 73.1454 eV.

Wavelength (nm)  n_x        k_x        a_x        R_x        T_x        A_x        E_x
100    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
105    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
110    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
115    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
120    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
125    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
130    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
135    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
140    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
145    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
150    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
155    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
160    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
165    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
170    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
175    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
180    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
185    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
190    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
195    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
200    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
205    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
210    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
215    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
220    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
225    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
230    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
235    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
240    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
245    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
250    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
255    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
260    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
265    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
270    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
275    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
280    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
285    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
290    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
295    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
300    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
305    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
310    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
315    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
320    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
325    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
330    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
335    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
340    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
345    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
350    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
355    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
360    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
365    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
370    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
375    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
380    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
385    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
390    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
395    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
400    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
405    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
410    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
415    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
420    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
425    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
430    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
435    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
440    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
445    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
450    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
455    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
460    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
465    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
470    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
475    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
480    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
485    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
490    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
495    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
500    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
505    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
510    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
515    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
520    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
525    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
530    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
535    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
540    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
545    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
550    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
555    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
560    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
565    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
570    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
575    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
580    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
585    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
590    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
595    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
600    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
605    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
610    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
615    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
620    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
625    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
630    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
635    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
640    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
645    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
650    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
655    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
660    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
665    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
670    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
675    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
680    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
685    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
690    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
695    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
700    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
705    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
710    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
715    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
720    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
725    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
730    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
735    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
740    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
745    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
750    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
755    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
760    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
765    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
770    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
775    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000
780    1.00000    0.00000    0.00000    0.00000    1.00000    0.00000    0.00000

$$$$
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