Modified regional self-interaction corrected time-dependent density functional theory for core excited-state...

Area of Science:

• Quantum Chemistry
• Computational Physics
• Spectroscopy

Background:

• Time-dependent density functional theory (TDDFT) is a key method for calculating electronic excitation energies.
• Existing methods like regional self-interaction correction (RSIC) have limitations in accurately describing core-excitation energies.
• Gaussian basis functions can struggle with the nuclear-electron cusp, impacting accuracy.

Purpose of the Study:

• To develop an improved method for accurate core-excitation energy calculations within TDDFT.
• To address the limitations of the RSIC method by incorporating higher atomic orbitals.
• To enhance the description of the nuclear-electron cusp in Gaussian basis sets.

Main Methods:

• A modified regional self-interaction correction (mRSIC) method was developed.
• The mRSIC method was integrated with a long-range correction (LC) scheme.
• The combined scheme was applied to calculate various excitation energies.

Main Results:

• The mRSIC method accounts for energy contributions from 2s and higher atomic orbitals, unlike the original RSIC.
• mRSIC improves the description of the nuclear-electron cusp for Gaussian basis functions.
• Combining mRSIC with LC significantly enhanced the accuracy of core-excitation energies.
• The combined scheme maintained the accuracy of valence, Rydberg, and charge transfer (CT) excitation energies.

Conclusions:

• The developed mRSIC method, when combined with LC, provides accurate core-excitation energies.
• This integrated approach achieves high accuracy across all types of electronic excitation energies.
• The new method offers a robust tool for advanced TDDFT calculations.