2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/127455We discuss the relationship between modern time-dependent density functional theory and earlier time-periodic versions, and why the criticisms in a recent paper (Chem. Phys. Lett. {\bf 433} (2006) 204) of our earlier analysis (Chem. Phys. Lett. {\bf 359} (2002) 237) are incorrect.Will appear as a Comment in CPL, on the paper cited above that is also available at arXiv:cond-mat/0611428Materials Sciencetext