DFT results against experimental data for electronic properties of C60 and C70 fullerene derivatives

Some electronic properties of different C-60 and C-70 derivatives were evaluated using 20 density functionals (the B3LYP, BHANDH, PBEO, HSE06, CAM-B3LYP, omega B97X-D, iota-BMK, iota-PBEPBE, M06-L, M06, M06-2X, M06-HF, PW91PW91, BLYP, B97D, HCT407, T-HCTH, T-HCTHhyb, TPSS, and LSDA), and some of the results were compared with the available experimental data. Unlike in Hartree-Fock (HF) method, the orbital relaxation is not the origin of the violation of DFT from the Koopmans' theorem. For most of functionals, the HOMO-LUMO gap (Eg) is more sensitive to the functional compared to the optical gap. The functionals with a large %HF exchange significantly overestimate the Eg, and are not suggested for electronic calculations. All non-hybrid functionals underestimate the value of !HOMO' in comparison to the experimental ionization potential (IPe). In the hybrid functionals, the HOMO level becomes more stable by increasing %HF exchange and even in some functionals with a large %HF,IHOMOI overestimates the IPe. (C) 2018 Elsevier Inc. All rights reserved.