My Community

Dear VASP masters,

In the GW_BSE calculations, the exciton states and oscillator strength are list in vasprun.xml.
as following:

We know that the exciton state energy is in eV, My question is what is the unit for the send column oscillator strength in VASP, are they in Hartree atomic unit? or it is a dimensionless quantity? with no unit?

as following:
"
...
<varray name="opticaltransitions" >
...
<v> 0.384 0.000 </v>
<v> 12.839 157807.854 </v>
<v> 12.843 155408.811 </v>
<v> 12.847 153130.856 </v>
<v> 13.654 0.011 </v>
<v> 13.655 0.016 </v>
<v> 13.656 0.025 </v>
<v> 13.725 0.000 </v>
<v> 13.726 0.000 </v>
<v> 13.769 0.023 </v>
<v> 13.770 0.043 </v>
<v> 13.770 0.073 </v>
<v> 13.844 23202.807 </v>
<v> 13.846 22712.837 </v>
<v> 13.847 22259.792 </v>
<v> 13.871 0.000 </v>
<v> 13.988 0.061 </v>
<v> 13.988 0.052 </v>
<v> 13.988 0.059 </v>
<v> 13.995 0.001 </v>
<v> 13.995 0.002 </v>
<v> 13.996 0.003 </v>
<v> 14.004 0.633 </v>
...
"

Thak you very much!

Dear Hong,

The oscillator strength expresses the probability of the transition, so it is a dimensionless quantity.