Unraveling the Excited-State Dynamics of Eosin Y Photosensitizers Using Single-Molecule Spectroscopy

2019 ◽  
Vol 123 (13) ◽  
pp. 2592-2600
Author(s):  
Pauline G. Lynch ◽  
Huw Richards ◽  
Kristin L. Wustholz
Keyword(s):  
Excited State ◽  
Single Molecule ◽  
Eosin Y ◽  
Single Molecule Spectroscopy ◽  
Excited State Dynamics

Regulating the femtosecond excited-state lifetime of a single molecule

Science ◽  
2018 ◽  
Vol 361 (6406) ◽  
pp. 1012-1016 ◽  
Author(s):  
K. R. Rusimova ◽  
R. M. Purkiss ◽  
R. Howes ◽  
F. Lee ◽  
S. Crampin ◽  
...  
Keyword(s):  
Excited State ◽  
Single Molecule ◽  
Scanning Tunneling Microscope ◽  
Scanning Tunneling ◽  
Initial Condition ◽  
Excited State Lifetime ◽  
Invariant Surface ◽  
Ionic State ◽  
Tunneling Microscope ◽  
Excited State Dynamics

The key to controlling reactions of molecules induced with the current of a scanning tunneling microscope (STM) tip is the ultrashort intermediate excited ionic state. The initial condition of the excited state is set by the energy and position of the injected current; thereafter, its dynamics determines the reaction outcome. We show that a STM can directly and controllably influence the excited-state dynamics. For the STM-induced desorption of toluene molecules from the Si(111)-7x7 surface, as the tip approaches the molecule, the probability of manipulation drops by two orders of magnitude. A two-channel quenching of the excited state is proposed, consisting of an invariant surface channel and a tip height–dependent channel. We conclude that picometer tip proximity regulates the lifetime of the excited state from 10 femtoseconds to less than 0.1 femtoseconds.

Ultrafast single-molecule photonics: Excited state dynamics in coherently coupled complexes

2008 ◽  
Vol 128 (5-6) ◽  
pp. 1050-1052 ◽  
Author(s):  
Jordi Hernando ◽  
Jacob Hoogenboom ◽  
Erik van Dijk ◽  
Maria Garcia-Parajo ◽  
Niek F. van Hulst
Keyword(s):  
Excited State ◽  
Single Molecule ◽  
Excited State Dynamics

Excited-State Dynamics in the RNA Nucleotide Uridine 5’-Monophosphate Investigated by Femtosecond Broadband Transient Absorption Spectroscopy

2019 ◽  
Author(s):  
Matthew M. Brister ◽  
Carlos Crespo-Hernández
Keyword(s):  
Excited State ◽  
Excited States ◽  
Ground State ◽  
Transient Absorption ◽  
Electronic Energy ◽  
Transient Absorption Spectroscopy ◽  
Electronic Relaxation ◽  
Vibrationally Excited ◽  
Excited State Dynamics ◽  
Π State

<p></p><p> Damage to RNA from ultraviolet radiation induce chemical modifications to the nucleobases. Unraveling the excited states involved in these reactions is essential, but investigations aimed at understanding the electronic-energy relaxation pathways of the RNA nucleotide uridine 5’-monophosphate (UMP) have not received enough attention. In this Letter, the excited-state dynamics of UMP is investigated in aqueous solution. Excitation at 267 nm results in a trifurcation event that leads to the simultaneous population of the vibrationally-excited ground state, a longlived <sup>1</sup>n<sub>O</sub>π* state, and a receiver triplet state within 200 fs. The receiver state internally convert to the long-lived <sup>3</sup>ππ* state in an ultrafast time scale. The results elucidate the electronic relaxation pathways and clarify earlier transient absorption experiments performed for uracil derivatives in solution. This mechanistic information is important because long-lived nπ* and ππ* excited states of both singlet and triplet multiplicities are thought to lead to the formation of harmful photoproducts.</p><p></p>

Modulation of Excited State Dynamics in Lead Halide Perovskite Films with Electrical Bias

2019 ◽  
Author(s):  
Gergely Samu ◽  
R.A. Scheidt ◽  
A. Balog ◽  
C. Janáky ◽  
P.V. Kamat
Keyword(s):  
Excited State ◽  
Excited State Dynamics ◽  
Halide Perovskite ◽  
Electrical Bias ◽  
Lead Halide
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