Mapping electronic decoherence pathways in molecules.

Area of Science:

• Physical Chemistry
• Quantum Mechanics
• Spectroscopy

Background:

• Understanding molecular electronic quantum decoherence is crucial but challenging.
• Existing methods struggle to isolate decoherence pathways influenced by vibrations and solvents.

Purpose of the Study:

• To develop a strategy for isolating and analyzing electronic decoherence pathways in molecular systems.
• To elucidate how quantum coherence is lost in molecular chromophores within condensed phase environments.

Main Methods:

• Utilized resonance Raman spectroscopy to reconstruct complex molecular spectral densities at room temperature.
• Developed a quantitative method to capture decoherence dynamics from spectral densities.
• Decomposed overall coherence loss into contributions from specific molecular and solvent modes.

Main Results:

• Demonstrated the strategy on the DNA base thymine in water, showing decoherence decay in ~30 fs.
• Identified intramolecular vibrations as key to early-time decoherence and solvent interactions for overall decay.
• Found that hydrogen bonding significantly accelerates decoherence, while temperature enhances solvent contributions.

Conclusions:

• The developed strategy effectively connects molecular structure to quantum decoherence.
• This approach enables the rational design of chemical strategies to modulate quantum decoherence.