| Autor: |
Beckstead, Ashley A., Zhang, Yuyuan, Hilmer, Jonathan K., Smith, Heidi J., Bermel, Emily, Foreman, Christine M., Kohler, Bern |
| Zdroj: |
The Journal of Physical Chemistry - Part A; 20240101, Issue: Preprints |
| Abstrakt: |
The photophysical properties of the natural pigment violacein extracted from an Antarctic organism adapted to high exposure levels of UV radiation were measured in a combined steady-state and time-resolved spectroscopic study for the first time. In the low-viscosity solvents methanol and acetone, violacein exhibits low fluorescence quantum yields on the order of 10-4, and femtosecond transient absorption measurements reveal excited-state lifetimes of 3.2 ± 0.2 and 4.5 ± 0.2 picoseconds in methanol and acetone, respectively. As solvent viscosity is increased, both the fluorescence quantum yield and excited-state lifetime of this intensely colored pigment increase dramatically and stimulated emission decays 30-fold more slowly in glycerol than in methanol at room temperature. Excited-state deactivation is suggested to occur via a molecular-rotor mechanism in which torsion about an interring bond leads to a conical intersection with the ground state. |
| Databáze: |
Supplemental Index |
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