Time Resolved Photoelectron Spectroscopy of Thioflavin T Photoisomerization: A Simulation Study

The excited state isomerization of thioflavin T (ThT) is responsible for the quenching of its fluorescence in a nonrestricted environment. The fluorescence quantum yield increases substantially upon binding to amyloid fibers. Simulations reveal that the variation of the twisting angle between benzothiazole and benzene groups (ϕ₁) is responsible for the subpicosecond fluorescence quenching. The evolution of the twisting process can be directly probed by photoelectron emission with energies ε ≥ 1.0 eV before the molecule reaches the ϕ₁-twisted configuration (∼300 fs).