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We resolved a key issue in real-time time-dependent density functional theory (TDDFT) by updating Kohn-Sham orbitals dynamically. This corrects electron density and improves predictions of physical properties in quantum systems.

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Area of Science:

  • Quantum Chemistry
  • Computational Physics
  • Theoretical Chemistry

Background:

  • The Kohn-Sham formulation is standard in time-dependent density functional theory (TDDFT).
  • Conventional TDDFT faces challenges with unphysical multielectron excitations.
  • These excitations arise from fixed orbital counts and occupations during time propagation.

Purpose of the Study:

  • To address fundamental limitations in the conventional Kohn-Sham formulation of real-time TDDFT.
  • To develop a new formulation that corrects unphysical multielectron excitations.
  • To ensure accurate electron density and reliable prediction of physical properties.

Main Methods:

  • Proposed a novel formulation for real-time TDDFT.
  • Implemented on-the-fly updates for Kohn-Sham orbitals and their occupations.
  • Simulated Rabi oscillations for validation.

Main Results:

  • The new formulation successfully removes unphysical multielectron excitations.
  • Accurate electron density is determined by the revised method.
  • Simulations of Rabi oscillations show agreement with analytical results for noninteracting electrons.

Conclusions:

  • The proposed dynamic update of Kohn-Sham orbitals resolves a fundamental issue in real-time TDDFT.
  • This advancement leads to more accurate predictions of electronic properties.
  • The method offers a reliable approach for studying quantum dynamics.