Photoinduced long-lived charge transfer excited states in AT-DNA strands

2016 ◽  
Vol 18 (31) ◽  
pp. 21241-21245 ◽  
Author(s):  
Lara Martinez-Fernandez ◽  
Yuyuan Zhang ◽  
Kimberly de La Harpe ◽  
Ashley A. Beckstead ◽  
Bern Kohler ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Electronic State ◽  
Excited States ◽  
Ir Spectrum ◽  
Excited Electronic State ◽  
Single Strand ◽  
Dna Strands ◽  
A Charge ◽  
First Time

The IR spectrum of a charge transfer (CT) excited electronic state in DNA has been computed for the first time, enabling assignment of the long-lived component of the transient IR spectrum of a d(AT)9 single strand to an A → T CT state.

CHAMELEON GROUND STATE AND EXCITED STATES OF EDT-TTF-IM-F4TCNQ RADICAL DYAD IN DIFFERENT ENVIRONMENTS

2012 ◽  
Vol 11 (03) ◽  
pp. 505-525 ◽  
Author(s):  
YUHUA ZHOU ◽  
KAI TAN ◽  
XIN LU
Keyword(s):  
Charge Transfer ◽  
Solid State ◽  
Excited States ◽  
Ground State ◽  
Density Functional ◽  
Solvent Polarity ◽  
Functional Study ◽  
Polar Solvents ◽  
Model Calculations ◽  
A Charge

We have performed a systematic density functional study on the ground-state electronic structure and excited states of a representative D-σ-A dyad, i.e. EDT-TTF-Im-F4TCNQ π-radical, in vacuo and in different conventional solvents (toluene, THF, DMF and DMSO) by using some popular hybrid density functionals (B3LYP, M05, M05-2X, PBE0 and BMK). It has been shown that the M05 and B3LYP functionals perform the best in predicting the intramolecular charge-transfer (ICT) pertaining to both the ground state and excited states of the dyad. The amphoteric dyad is liable to solvent-promoted ICT from its EDT-TTF-Im donor (D) to F4TCNQ acceptor (A), adopting a charge-unseparated ground state D-A• in vacuo, a partially zwitterionic ground state [D-A]• in nonpolar toluene solvent, and a fully zwitterionic ground state D•+-A- in such polar solvents as THF, DMF and DMSO. Owing to its solvent-dependent chameleon ground state, excited states of the dyad in solvents also exhibit remarkable dependence on solvent polarity, as revealed by TDDFT calculations. Furthermore, cluster model calculations revealed that intermolecular charge-transfer readily occurs between the dyads, accounting for the observed zwitterionic charge state in solid state and solid-state semiconductivity.

Nature and characterization of the singlet and triplet excited states of the dibenzylideneacetone and di-3-(N-ethylcarbazoylidene)acetone bridging ligands

1992 ◽  
Vol 70 (11) ◽  
pp. 2777-2784 ◽  
Author(s):  
Pierre D. Harvey ◽  
Benoit Daoust
Keyword(s):  
Excited States ◽  
Model Compound ◽  
Energy Transition ◽  
Quantum Yields ◽  
Bridging Ligands ◽  
Fluorescence Quantum Yields ◽  
A Charge ◽  
Triplet Excited States ◽  
First Time

The lowest energy singlet state in di-3-(N-ethylcarbazoylidene)acetone (dNECa), a luminescent model compound at room temperature for dibenzylideneacetone (dba), has been assigned to a charge transfer (CT) state using the medium polarity effect on λmax(F) and the fluorescence polarized spectra of dNECa at 77 K. The dNECa fluorescence quantum yields [Formula: see text] and lifetimes (τF) are solvent sensitive where both [Formula: see text] and τF tend to increase with polarity. The very weak and moderately structured phosphorences have been located for the first time for both dba and dNECa in the 550–800 nm range and are also assigned to a CT state. In this case the CT interactions are less pronounced than λ(0–0)P and τP are much less solvent sensitive. Finally, EHMO type calculations confirm that the CT transition is the lowest energy transition in dba and di-3-(N-methylindoylidene)acetone (a model compound for dNECa), but also suggest that the nπ* state must lie near the CT state in dba.

scholarly journals Disentangling thermal and nonthermal excited states in a charge-transfer insulator by time- and frequency-resolved pump-probe spectroscopy

2009 ◽  
Vol 80 (23) ◽  
Author(s):  
Claudio Giannetti ◽  
Goran Zgrablic ◽  
Cristina Consani ◽  
Alberto Crepaldi ◽  
Damiano Nardi ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Pump Probe ◽  
A Charge ◽  
Probe Spectroscopy

An ultra-broadband perovskite-PbS quantum dot sensitized carbon nanotube photodetector

Nanoscale ◽  
2018 ◽  
Vol 10 (19) ◽  
pp. 9044-9052 ◽  
Author(s):  
Ibrahima Ka ◽  
Luis F. Gerlein ◽  
Ivy M. Asuo ◽  
Riad Nechache ◽  
Sylvain G. Cloutier
Keyword(s):  
Charge Transfer ◽  
Carbon Nanotube ◽  
Quantum Dot ◽  
Hybrid System ◽  
Hybrid Material ◽  
Spectral Response ◽  
Halide Perovskite ◽  
A Charge ◽  
First Time ◽  
Pbs Quantum Dot

A nano-engineered hybrid material consisting of SWCNTs, PbS-QDs and a halide perovskite is developed for the first time. The PbS-QDs in the hybrid system are found to be a charge generator and a charge-transfer facilitator. The hybrid material integrated into photoconductive devices shows a broad spectral response.

scholarly journals Interplay Between Locally Excited and Charge Transfer States Governs the Photoswitching Mechanism in Fluorescent Protein Dreiklang

2020 ◽  
Author(s):  
TIRTHENDU SEN ◽  
Yingying Ma ◽  
Igor Polyakov ◽  
Bella Grigorenko ◽  
Alexander Nemukhin ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Excited State ◽  
Charge Transfer ◽  
Excited States ◽  
Fluorescent Protein ◽  
Locally Excited ◽  
Structure And Dynamics ◽  
Dynamics Simulations ◽  
A Charge ◽  
High Level

<div>We present the results of high-level electronic structure and dynamics simulations</div><div>of the photoactive protein Dreiklang. With the goal to understand the details of</div><div>Dreiklang's photocycle, we carefully characterize the excited states of the ON- and</div><div>OFF-forms of Dreiklang. The key ?nding of our study is the existence of a lowlying</div><div>excited state of a charge-transfer (CT) character in the neutral ON form and</div><div>that population of this state, which is nearly isoenergetic with the locally excited</div><div>(LE) bright state, initiates series of steps ultimately leading to the formation of</div><div>the hydrated dark chromophore (OFF state). These results allow us to re?ne the</div><div>mechanistic picture of the Dreiklang's photocycle and photoactivation.</div>

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