title: A dual-level state-specific time-dependent density-functional theory.
abstract: A highly efficient new algorithm for time-dependent density-functional theory (TDDFT) calculations is presented. In this algorithm, a dual-level approach to speed up DFT calculations (Nakajima and Hirao, J Chem Phys 2006, 124, 184108) is combined with a state-specific (SS) algorithm for TDDFT (Chiba et al., Chem Phys Lett 2006, 420, 391). The dual-level SS-TDDFT algorithm was applied to excitation energy calculations of typical small molecules, the Q bands of the chlorophyll A molecule, the charge-transfer energy of the zincbacteriochlorin-bacteriochlorin model system, and the lowest-lying excitation of the circumcoronene molecule. As a result, it was found that the dual-level SS-TDDFT gave correct excitation energies with errors of 0.2-0.3 eV from the standard TDDFT approach, with much lower CPU times for various types of excitation energies of large-scale molecules.
authors.affiliation: Department of Applied Chemistry, School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.
authors.forename: Seiken
authors.initials: S
authors.lastname: Tokura
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sato
authors.forename: Takao
authors.initials: T
authors.lastname: Tsuneda
authors.forename: Takahito
authors.initials: T
authors.lastname: Nakajima
authors.forename: Kimihiko
authors.initials: K
authors.lastname: Hirao