Get Excited: First-principles Investigation of Chromophores on DNA Scaffolding

Document Type

Student Presentation

Presentation Date

April 2016

Faculty Sponsor

Lan Li


The understanding of first principle energy transport through organic molecules may prove a fundamental scientific observation for novel energy harvesting systems, quantum computing, and solar power energy transportation and production. The focus of the project will be to investigate functional groups of organic molecules, specifically the chromophoric red dye DiSC2(5) and its interaction with DNA, which has unique addressability. DiSC2(5), also named Cy5, exhibit bright fluorescence signals and have shown promising lossless exciton transport properties; as well as, tunable energy absorption and emission when conjoined with the DNA system. Density functional theory (DFT) and time dependent density functional theory (TD-DFT) will be used to investigate the chromophore Cy5 in vertically stacked (H-aggregates) and slipped assembly dyes (J-aggregates) arrangements, with the goal of computationally predicting optimized structural characteristics and hypsochromic and bathochromic exciton behavior. While prior methods of TD-DFT show poor performance for charge-transfer electronic transitions, we propose that the utilization of hybrid functionals; specifically B3LYP and BH&HLYP exchange-correlation (XC) functionals, provides reasonable results for the excitation energy and potential energy surfaces. Resultant excitation energies and frequency-dependent response properties will be used to advance the understanding of experimentally derived Förester resonance energy transfer (FRET) observations and guide future experiments.

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