Theoretical Description of Excited States and Optical Properties of Transition Metal Complexes in the Framework of the Bethe–Salpeter Equation

Optical properties of mono- and oligonuclear transition metal complexes have been investigated theoretically using the Bethe-Salpeter equation (BSE) approach applied within the GW approximation and compared to experiment. The BSE formalism is equally efficient to the time-dependent density functional theory (TDDFT), while it can overcome the charge-transfer (CT) problems associated with the latter. The performance of the GW/BSE method has been assessed for molecular excitation energies, and its application to the real-world coinage metal complexes has been validated.