Large-Scale Molecular Dynamics Simulation for Ground and Excited States Based on Divide-and-Conquer Long-Range...

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Materials Science

Background:

• Density-functional tight-binding (DFTB) methods often underestimate electronic energy gaps.
• Accurate calculation of energy gaps is crucial for understanding molecular properties and reactions.
• Long-range interactions are important for describing electronic properties in condensed phases.

Purpose of the Study:

• To develop and implement long-range corrected (LC) divide-and-conquer (DC) DFTB and TD-DFTB methods.
• To address the underestimation of energy gaps in standard DFTB calculations.
• To enhance the efficiency and accuracy of computational methods for molecular systems.

Main Methods:

• Implementation of a long-range correction (LC) term using an entrywise product.
• Development of divide-and-conquer (DC) based density-functional tight-binding (DFTB) and time-dependent DFTB (TD-DFTB) methods.
• Application of the DC-TD-LCDFTB method to model excited-state intramolecular proton transfer.

Main Results:

• The developed LC-DFTB and TD-DFTB methods effectively resolve the underestimation of energy gaps.
• Efficient implementation of the LC term using the entrywise product for computational speed-up.
• Demonstrated accuracy and efficiency of the DC-TD-LCDFTB method on formaldehyde and 2,2'-bipyridine-3,3'-diol systems.

Conclusions:

• The novel DC-TD-LCDFTB method provides accurate and efficient calculations of electronic properties.
• This approach improves the modeling of molecular systems, particularly those involving excited-state phenomena.
• The developed methods offer a valuable tool for advancing research in computational chemistry and materials science.