Bethe-Salpeter equation
VASP can compute the frequency-dependent dielectric function with excitonic effects based on the Bethe-Salpeter equation. The calculation can be done on top of the electronic ground-state within DFT, using a hybrid functional or the GW approximation.
Content
Further resources
Also check out the BSE category on the VASP Wiki for a detailed documentation of BSE features implemented in VASP.