Accelerating Excitation Energy Computation in Molecules and Solids within Linear-Response Time-Dependent Density...

Area of Science:

• Computational Chemistry
• Materials Science
• Quantum Mechanics

Background:

• Calculating excitation energies is crucial for understanding molecular and solid-state optoelectronic properties.
• Conventional linear-response time-dependent density functional theory (LR-TDDFT) methods are computationally expensive, limiting their application to small systems.

Purpose of the Study:

• To develop an efficient computational method for calculating excitation energies using LR-TDDFT.
• To reduce the computational cost associated with LR-TDDFT calculations, enabling the study of larger and more complex systems.

Main Methods:

• The study introduces a novel approach combining interpolative separable density fitting (ISDF) with implicit construction and iterative diagonalization of the LR-TDDFT Hamiltonian.
• This method is implemented within a plane-wave basis set under periodic boundary conditions.

Main Results:

• The ISDF method accurately reproduces excitation energies for a fullerene (C60) molecule and a bulk silicon (Si64) system with significantly reduced computational cost compared to conventional methods.
• The efficiency of the ISDF method allows for the investigation of excited-state properties of liquid water interacting with MoS2 and phosphorene.

Conclusions:

• The developed ISDF-based LR-TDDFT method offers a computationally efficient pathway for determining excitation energies in molecules and solids.
• Aqueous environments exhibit a notable influence on high excitation energies of 2D semiconductors, impacting their photocatalytic water-splitting capabilities, while having a weaker effect on low excitation energies.