We have proposed advanced approximations for the Exchange-Correlation Kernel of TDDFT.
In 2003 (Phys. Rev. Lett. 91, 056402 (2003)) we have demonstrated that a new form (MP) for the Exchange-Correlation Kernel of TDDFT directly derived from approaches coming from Many-Body Quantum Field Theory and based on the succesful approximations of the latter (GW, Bethe-Salpeter approach), is able to correctly reproduce excitonic effects in the optical spectrum of infinite systems. The results are indistinguishable from what can be obtained by solving the cumbersome two-particle Bethe-Salpeter equation, and in very good agreement with the experiment. With respect to the LRC approximation, the MP is even able to reproduce bound excitons, like it is evident in the optical spectra of rare gas solids (in Solid Argon, the first three peeks of the excitonic, hydrogenic-like Balmer series are reproduced).

Optical Absorption of Solid Argon