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Title: Double, Rydberg and charge transfer excitations from pairing matrix fluctuation and particle-particle random phase approximation

Double, Rydberg, and charge transfer (CT) excitations have been great challenges for time-dependent density functional theory (TDDFT). Starting from an (N ± 2)-electron single-determinant reference, we investigate excitations for the N-electron system through the pairing matrix fluctuation, which contains information on two-electron addition/removal processes. We adopt the particle-particle random phase approximation (pp-RPA) and the particle-particle Tamm-Dancoff approximation (pp-TDA) to approximate the pairing matrix fluctuation and then determine excitation energies by the differences of two-electron addition/removal energies. This approach captures all types of interesting excitations: single and double excitations are described accurately, Rydberg excitations are in good agreement with experimental data and CT excitations display correct 1/R dependence. Furthermore, the pp-RPA and the pp-TDA have a computational cost similar to TDDFT and consequently are promising for practical calculations.
Authors:
 [1] ;  [1] ;  [2] ;  [3]
  1. Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States)
  2. (Belgium)
  3. Department of Chemistry and Department of Physics, Duke University, Durham, North Carolina 27708 (United States)
Publication Date:
OSTI Identifier:
22253842
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 139; Journal Issue: 22; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 97 MATHEMATICAL METHODS AND COMPUTING; DENSITY FUNCTIONAL METHOD; EXCITATION; FLUCTUATIONS; PARTICLES; RANDOM PHASE APPROXIMATION; REMOVAL; TIME DEPENDENCE