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Exploring the Conical Intersection Seam: The Seam Space Nudged Elastic Band Method
Toshifumi Mori1,2, Todd J Martínez1,2
1PULSE Institute and Department of Chemistry, Stanford University, Stanford, California 94305, United States.
Journal of Chemical Theory and Computation
|November 21, 2015
Summary
This study introduces a new method to map the full landscape of conical intersections (CIs) in molecules. The seam space nudged elastic band (SS-NEB) method reveals how minimum energy conical intersections (MECIs) are connected, offering insights into photoreaction pathways.
Area of Science:
- Theoretical and Computational Chemistry
- Quantum Chemistry
- Photochemistry
Background:
- Conical intersections (CIs) are crucial for understanding molecular photoreactions.
- Existing methods struggle to explore the multidimensional nature of CI seams beyond minimum energy points (MECIs).
Purpose of the Study:
- To develop and demonstrate a novel computational method for characterizing the complete seam space of conical intersections.
- To connect minimum energy conical intersections (MECIs) via minimum energy paths within the seam space.
Main Methods:
- Development of the seam space nudged elastic band (SS-NEB) method.
- Combining nudged elastic band (NEB) with gradient-projected MECI optimization.
- Application to ethylene and the green fluorescent protein (GFP) chromophore.
Main Results:
- The SS-NEB method efficiently finds minimum energy paths along CI seams.
- Demonstrated connectivity of previously known MECIs for ethylene and GFP chromophore within a single seam.
- Analysis suggests a broader range of seam geometries, not just MECIs, participate in nonadiabatic transitions.
Conclusions:
- The SS-NEB method provides a powerful tool for characterizing complex CI seam landscapes.
- Results support the topological connectivity of all MECIs in seam space.
- Highlights the importance of exploring extensive seam geometries for understanding nonadiabatic dynamics.
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