Understanding Molecular Electron Transfer:
DesigningChemical Logic GatesHoracio Carias
Duke UniversityDept. of Physics
Dept. of Chemistry
● Physics– Quantum Computing
● Chemistry– Redox Reactions– Molecular Electronics
● Biology– Photosynthesis– Vision
● Interdisciplinary– Solar Energy Conversion
Motivations
Chang Group – Duke Physics
ET research in Beratan Group● Molecular interferometers
– Orbitally forbidden interaction prevents ET from D A→● tDU = tDL, tUA = tLA
Skourtis, Waldeck, Beratan J. Phys. Chem. B Vol 108, No 40, 2004
( )fiif
DA EET −=Γ δπ
2
−
+−
≈LD
LADL
UD
UADUDA EE
ttEE
ttT 00,00
ET research in Beratan Group● Molecular interferometers
– Electron interaction with bridge oscillator labels pathway ● “Whichway” interferometer● XOR Gate
( ) ( )
−−−
≈UUDUD
UAUDUDA EEEE
ttTω
γ
10,00
Current Work and Future Directions
● Calculate tunneling rates in real molecule● Extend model to include photoexcitation of
bridge oscillator– IR pulse excites bridge oscillator– Electron picks up energy from oscillator enroute from
D A→● Model real molecule under influence of IR pulse
Acknowledgements
● Prof. David Beratan ● Prof. Spiros Skourtis – University of Cyprus● Prof. Johnathon Sessler – UT Austin● Prof. Igor Rubtsov – Tulane University● Dequan Xiao