Here, |t i | 2 are oscillator strengths of transitions with excitation energies E i , and Ω is the unit cell volume. The exciting code performs a Lorentzian broadening with a value of 0.2 eV in order to mimic the finite excitation lifetimes. Band contributions to the excitons were calculated from BSE eigenvectors as described in Ref. 34 (see Eq. ( ) there).