Efficient evaluation of atom tunneling combined with electronic structure calculations

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Materials Science

Background:

• Atomic rearrangements are crucial in chemical reactions and material properties.
• Accurately calculating tunneling rates is computationally challenging.
• Existing methods often struggle with complex, many-atom systems.

Purpose of the Study:

• To develop an efficient methodology for determining optimal tunneling paths.
• To accurately evaluate tunneling rates for atomic rearrangements.
• To provide a computationally feasible approach for complex systems.

Main Methods:

• Utilizing a nudged elastic band method extension for optimal path finding.
• Employing dynamics calculations to identify optimal Feynman paths for tunneling.
• Applying harmonic approximation for transition rate estimation.

Main Results:

• The method successfully calculates tunneling paths and rates for atomic rearrangements.
• Demonstrated efficiency in systems with many atoms, including electronic structure calculations.
• Accurate predictions for H3BNH3 dissociation and hydrogen diffusion in Ta crystals.

Conclusions:

• The developed methodology offers a robust way to study tunneling phenomena.
• This approach is applicable to both molecular and solid-state systems.
• The findings have implications for understanding chemical reactions and material diffusion.