Ultrafast excitonic dynamics in DNA: Bridging correlated quantum dynamics and sequence dependence

Area of Science:

• Computational Physics
• Molecular Biology
• Quantum Chemistry

Background:

• Photoexcitation of DNA creates bound electron-hole pairs (Frenkel excitons) via Coulomb interaction.
• Understanding exciton dynamics in DNA is key to its photophysical properties.

Purpose of the Study:

• To identify DNA sequences with long-lived excited states, high charge separation, and dipole moments.
• To correlate these properties with specific DNA sequence characteristics.

Main Methods:

• Utilized a tight-binding (TB) approach with established electron and hole parameters.
• Simulated 16,384 double-stranded DNA sequences (14 nucleobases each).
• Analyzed relaxation properties, charge separation, and dipole moments.

Main Results:

• Identified a subset of DNA sequences exhibiting long-lived excited states, high charge separation, and dipole moments.
• These sequences were found to be particularly thymine (T)-rich.
• Correlations remained robust against variations in electron-hole interaction strength.

Conclusions:

• Tight-binding simulations can predict DNA sequences with desirable photophysical properties.
• Thymine-rich sequences are promising candidates for applications requiring stable excitons.
• This interdisciplinary approach bridges quantum physics, chemistry, and genetics.