Concerning on your suspected that, “why I persist in using the time-dependent local spin density approximation (TD-LSDA) for calculating the optical properties of pristine and functionalized adamantane molecules?” which has been shown in previous report. My reason used (TD-LSDA) approximation because considering only the electronic results, when comparison is the nearest with the experimental data. From learn more about difference of the exchange-correlation, it found that local spin density (LSDA) and generalized gradient approximations (GGA) cannot describe bound excitonic states due to lack of an effective attractive Coulomb interaction between photo-excited electrons and holes; which are not accurate enough for describing quasi-particles (such as excitons etc.). In contrast, the hybrid density functional, include long-rang non-local and non-adiabatic corrections in from of a fraction of the exact exchange (Hartree-Fock), are able to reproduce the excitonic effects.
Therefore, authors have removed the optical absorption results of (TD-LSDA) and instead with (TD-B3LYP) results (as shown in table 3 and figure 1) in order to according with the ionization potential (IP) and the electron affinity (EA) results have been obtained from the same method.