Your question doesn't have a straightforward answer as comparing XC functionals is very difficult. Even if we limit the performance scope to TDDFT on D-A complexes, the behavior of functionals can vary widely with the system being studied. However, in general I think that hybrid functionals using a large portion of exact (i.e. HF) exchange will give you the best result. In FF 8.0.0 RC, the following functionals can be used with TDDFT:
Exchange Correlation Exchange-Correlation Hybrid SLATER VWN1RPA SVWN1RPA B1LYP B88 VWN5 BVWN1RPA BHHLYP XPW91 PW91LDA SVWN5 B1PW91 GILL96 LYP BVWN5 B3PW91 XPBE96 CPW91 SLYP B3LYP1 OPTX CPBE96 BLYP B3LYP5 GLYP O3LYP1 OLYP O3LYP5 XLYP X3LYP BPW91 PBE1PW91 PW91 PBE0 PBEPW91 PBE96
$DFT HFX(1)=0.75 $END
Finally, I would like to advise you to edit your original message and remove the last sentence as it might cause problems with your G09 license.
On Tue Aug 6 '13 5:51pm, Enrico wrote
>Hi, I'm performing TDDFT calculations on molecular D-A complexes, from what i read on literature one of better DFT functionals for such purposes is M06 (in particular the one with the doubled HF term). I read here in previous threads that these Mx functional are not implemented and they won't be implemented in FF for a while.
>In such circumstances i was wondering if any one of you could suggest me a good substitute of the M062x functional to be used in FF (or in general a good functional for UVvis prediction in donor-acceptor complexes where CT transition are involved).
>Enrico Chiavazza, PhD
>Univ. of Torino, Italy
[ This message was edited on Tue Aug 6 '13 at 10:04pm by the author ]