Two-level iterative solver for linear response time-dependent density functional theory with plane wave basis set

Area of Science:

• Computational Chemistry
• Materials Science
• Quantum Mechanics

Background:

• Accurate simulation of excited-state properties is crucial for understanding molecular and material behavior.
• Standard iterative algorithms for time-dependent density functional theory (TD-DFT) can be computationally expensive and require substantial storage.
• Linear response TD-DFT methods are essential for calculating excited-state properties.

Purpose of the Study:

• To develop and implement an efficient two-level iterative solver for linear response TD-DFT.
• To reduce the computational cost and storage requirements for excited-state simulations.
• To investigate photoinduced charge separation phenomena at material interfaces.

Main Methods:

• Combined two forms of the Casida equation: Kohn-Sham orbital representation and Hutter's formulation.
• Implemented the solver using the plane wave pseudopotential method for excited-state simulations.
• Utilized the Davidson algorithm for numerical studies.

Main Results:

• The two-level iterative solver significantly reduced computational cost and storage for molecules (benzene, fullerene) and low-dimensional semiconductors (MoS2, TiO2).
• Achieved accurate prediction of excited-state properties for the studied systems.
• Successfully investigated photoinduced charge separation of methanol on rutile TiO2(110) surface, confirming hole capture by methanol.

Conclusions:

• The developed two-level iterative solver offers a computationally efficient and accurate approach for excited-state TD-DFT calculations.
• This method is suitable for simulating both molecular and solid-state materials.
• The approach provides valuable insights into interfacial charge transfer processes, such as exciton dynamics in photocatalysis.