Tempel, DavidAspuru-Guzik, Alan2011-01-132010Tempel, David G., and Alán Aspuru-Guzik. Forthcoming. Theory of excitation broadening using time-dependent density functional theory for open quantum systems.http://nrs.harvard.edu/urn-3:HUL.InstRepos:4657437The Casida equations of linear response TDDFT are extended to calculate linear spectra of open quantum systems evolving according to a Markovian master equation. By mapping a many-body open quantum system onto an open, non-interacting Kohn-Sham system, extrinsic line broadening due to electron-bath coupling can be described exactly within TDDFT. The structure of the resulting matrix equations are analyzed for the generic case of electrons linearly coupled to a harmonic bath within Redfield theory. An approximate form of the exchange-correlation kernel based on first-order G\"orling-Levy perturbation theory is derived.en-USchemical physicsother condensed matterquantum physicsJournal Article2011-01-13