Real-Time Time-Dependent Density Functional Theory Simulations with Range-Separated Hybrid Functionals for Periodic...

Area of Science:

• Computational materials science
• Quantum chemistry
• Ultrafast spectroscopy

Background:

• Real-time time-dependent density functional theory (RT-TDDFT) is crucial for studying ultrafast phenomena.
• Standard RT-TDDFT approximations struggle with excitonic effects in periodic systems.
• Range-separated hybrid functionals (RSH) offer a promising solution for enhanced accuracy.

Purpose of the Study:

• To benchmark methods for implementing RT-TDDFT with RSH for periodic systems.
• To improve the accuracy of modeling ultrafast excitonic dynamics.
• To address challenges in treating Coulomb singularities and external field incorporation.

Main Methods:

• Benchmarking Coulomb singularity treatments: truncated Coulomb potential vs. auxiliary-function correction.
• Assessing gauge choices for external field incorporation in numerical atomic orbital calculations.
• Implementing and validating the RT-TDDFT-RSH approach for periodic systems.

Main Results:

• The auxiliary-function correction method demonstrates superior convergence and numerical stability for RSH.
• The hybrid gauge, incorporating position-dependent phases, provides more accurate excitonic absorption descriptions than the velocity gauge.
• The developed RT-TDDFT-RSH implementation significantly enhances accuracy for ultrafast excitonic dynamics.

Conclusions:

• The auxiliary-function correction and hybrid gauge are critical for accurate RT-TDDFT-RSH simulations.
• This work provides a more reliable computational tool for studying excitonic phenomena in materials.
• The improved methodology advances the understanding of ultrafast processes in periodic systems.