Floquet formulation of time-dependent density-functional theory is revisited
in light of its recent criticism [Maitra and Burke, Chem. Phys. Lett. 359
(2002), 237]. It is shown that Floquet theory is well founded and its criticism
has overlooked important points of both the Runge-Gross formalism and Floquet
formulation itself. We substantiate our analysis by examples similar to that
considered by Maitra and Burke.Comment: 17 pages, 2 figures. accepted for publication in "Chemical Physics
Letters
