Effect of dynamical BSE and self-consistent GW on fluorescence and adiabatic transition energies

Determine whether incorporating a frequency-dependent (dynamical) kernel in the Bethe–Salpeter equation and/or adopting partial or fully self-consistent GW in the quasiparticle step reduces the errors in fluorescence and adiabatic S0→S1 transition energies relative to static BSE@GW calculations.

Background

The paper assesses excited-state geometries and transition energies using several BSE@GW variants and observes that static BSE@GW@HF tends to overestimate transition energies, while using a BHLYP starting point improves accuracy for absorption and fluorescence. Prior work demonstrated that including dynamical (frequency-dependent) effects in the BSE kernel yields a red-shift of absorption energies, improving their accuracy for small molecules.

Building on these observations, the authors explicitly note that it remains unknown whether similar dynamical effects would also reduce the errors in fluorescence and adiabatic transition energies. They further state that this question equally applies when considering partial or fully self-consistent GW procedures, indicating an unresolved methodological question about how these extensions impact non-vertical (emission and adiabatic) transitions.