A long-range-corrected time-dependent density functional theory

摘要

We apply the long-range correction (LC) scheme for exchange functional of density functional theory to time-dependent density functional theory (TDDFT) and examine its efficiency in dealing with the serious problems of TDDFT,i.e.,the underestimations of Rydberg excitation energies,oscillator strengths,and charge-transfer excitation energies.By calculating vertical excitation energies of typical molecules,it was found that LC-TDDFT gives accurate excitation energies,within an error of 0.5 eV,and reasonable oscillator strengths,while TDDFT employing a pure functional provides 1.5 eV lower excitation energies and two orders of magnitude lower oscillator strengths for the Rydberg excitations.It was also found that LC-TDDFT clearly reproduces the correct asymptotic behavior of the charge-transfer excitation energy of ethylene-tetrafluoroethylene dimer for the long intramolecular distance,unlike a conventional far-nucleus asymptotic correction scheme.It is,therefore,presumed that poor TDDFT results for pure functionals may be due to their lack of a long-range orbital-orbital interaction.