Implementation of real-time TDDFT for periodic systems in the open-source PySCF software package

Area of Science:

• Computational Chemistry
• Materials Science
• Quantum Mechanics

Background:

• Accurate simulation of excited-state dynamics is crucial for understanding chemical reactions and material properties.
• Existing methods often face limitations in handling periodic systems and real-time dynamics.
• Density Functional Theory (DFT) is a powerful tool, but its time-dependent extension (TDDFT) for dynamics requires efficient implementations.

Purpose of the Study:

• To introduce a novel implementation of real-time time-dependent density functional theory (RT-TDDFT) within the PySCF software package.
• To enable the calculation of excited-state dynamics for periodic systems, including surfaces, condensed phases, and molecular systems.
• To provide an accessible and modifiable tool for researchers in chemistry and materials science.

Main Methods:

• Developed a new RT-TDDFT module in the open-source PySCF package.
• Utilized Gaussian basis functions and a velocity gauge formalism for calculations.
• Applied the method to various benchmark systems, including molecular clusters on surfaces and bulk materials.

Main Results:

• Successfully performed optical absorption calculations for molecular and bulk systems.
• Simulated real-time field-induced dynamics of a (ZnO)4 molecular cluster on graphene.
• Calculated optical responses to infinitesimal fields and real-time charge-transfer dynamics under strong laser fields.

Conclusions:

• The new RT-TDDFT implementation in PySCF is a versatile tool for excited-state dynamics of periodic systems.
• The open-source nature and Python base facilitate easy modification and integration into research workflows.
• This advancement offers new capabilities for studying chemical and material dynamics in real-time.