Davis Computational Spectroscopy Workflow-From Structure to Spectra.

Area of Science:

• Computational Materials Science
• Condensed Matter Physics
• Quantum Chemistry

Background:

• Accurate prediction of material properties requires sophisticated simulation methods.
• Investigating the link between atomic structure, dynamics, and observable spectra like INS is computationally intensive.
• Existing methods often face limitations in speed and accuracy for complex systems.

Purpose of the Study:

• To establish an automated workflow integrating various atomic simulation tools.
• To investigate the relationship between atomic structure, lattice dynamics, material properties, and INS spectra.
• To introduce and validate the Chebyshev interaction model for efficient simulation (ChIMES) for enhanced accuracy in density functional tight binding (DFTB) simulations.

Main Methods:

• Utilized the Atomic Simulation Environment (ASE) as a central interface.
• Employed density functional theory (DFT) and DFTB for structure optimization and force constant calculations.
• Implemented the Chebyshev interaction model for efficient simulation (ChIMES) as a machine-learning force field.
• Computed phonon frequencies and eigenvectors for INS spectra simulation.
• Assessed the transferability of DFTB/ChIMES models across different training sets.

Main Results:

• The workflow successfully simulates INS spectra for crystalline and molecular solids.
• DFTB/ChIMES achieves approximately 100x reduction in computational cost compared to DFT.
• DFTB/ChIMES retains significant accuracy of DFT while demonstrating high performance for out-of-training set materials.
• The developed workflow enables accurate prediction of properties for complex structures.

Conclusions:

• The automated workflow provides a powerful platform for materials simulation.
• DFTB/ChIMES offers a computationally efficient and accurate alternative to traditional ab initio methods.
• This approach expands the scope of predictive materials simulations for complex systems.