Extended Mixed-Reference Spin-Flip Time-Dependent Density Functional Theory for Charge-Transfer State
Minseok Oh1, Nakhyun Kim1, YounJoon Jung1
1Department of Chemistry, Seoul National University, Seoul 08826, South Korea.
Journal of Chemical Theory and Computation
|June 9, 2026
Summary
We introduce an enhanced computational method, extended mixed-reference spin-flip time-dependent density functional theory (EMRSF-TDDFT), for more accurate molecular modeling. This new approach improves calculations for ground and excited states, particularly for charge transfer processes.
Area of Science:
- Quantum Chemistry
- Computational Physics
- Theoretical Chemistry
Background:
- Mixed-reference spin-flip time-dependent density functional theory (MRSF-TDDFT) is a method for calculating electronic excited states.
- Conventional MRSF-TDDFT has limitations in capturing certain electronic configurations crucial for accurate excited-state descriptions.
Purpose of the Study:
- To introduce a novel computational method, extended MRSF-TDDFT (EMRSF-TDDFT).
- To incorporate electronic configurations from linear-response TDDFT into the MRSF-TDDFT framework.
- To improve the description of orbital relaxation effects in excited-state calculations.
Main Methods:
- The formulation of EMRSF-TDDFT is based on the theoretical connection between linear-response and MRSF time-dependent Hartree-Fock theories.
- The method is extended to the time-dependent density functional theory (TDDFT) level.
- Benchmark calculations were performed on representative molecular systems.
Main Results:
- The newly introduced electronic configurations significantly contribute to orbital relaxation effects.
- EMRSF-TDDFT stabilizes both ground and excited states described in the triplet-reference orbital basis.
- The improved stabilization leads to better agreement with high-level theoretical reference data.
Conclusions:
- The developed EMRSF-TDDFT model offers enhanced accuracy for excited-state calculations.
- The method effectively captures crucial orbital relaxation effects.
- EMRSF-TDDFT is expected to be particularly applicable to photochemical processes involving charge transfer.
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