Unravelling the early photochemical behavior of (8-substituted-7-hydroxyquinolinyl)methyl acetates through electronic structure theory and ultrafast transient absorption spectroscopy

2017 ◽  
Vol 19 (2) ◽  
pp. 1089-1096 ◽  
Author(s):  
Jiani Ma ◽  
Jan-Michael Mewes ◽  
Kyle T. Harris ◽  
Timothy M. Dore ◽  
David Lee Phillips ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Excited State ◽  
Excited States ◽  
Transient Absorption ◽  
Electronic Structure Theory ◽  
Transient Absorption Spectroscopy ◽  
Structure Theory ◽  
Proton Transfers ◽  
Role Of Solvent

Role of solvent, prototropic states, excited state proton transfers, and excited states on biological effector release from quinoline-based phototriggers.

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>

Photoinduced ligand dissociation follows reverse energy gap law: nitrile photodissociation from low energy 3MLCT excited states

2020 ◽  
Vol 56 (29) ◽  
pp. 4070-4073
Author(s):  
Lauren M. Loftus ◽  
Jeffrey J. Rack ◽  
Claudia Turro
Keyword(s):  
Excited State ◽  
Excited States ◽  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Energy Gap ◽  
Low Energy ◽  
Transient Absorption Spectroscopy ◽  
Ligand Dissociation ◽  
Energy Gap Law

Transient absorption spectroscopy is used to show that stabilization of the 3MLCT excited state in a series of Ru(ii) complexes leads to decreased population of the 3LF state, but does not reduce the efficiency of photoinduced nitrile dissociation.

Effect of Aggregation on the Excited-State Electronic Structure of Perylene Studied by Transient Absorption Spectroscopy

2006 ◽  
Vol 110 (20) ◽  
pp. 6465-6471 ◽  
Author(s):  
Akihiro Furube ◽  
Miki Murai ◽  
Yoshiaki Tamaki ◽  
Sadayuki Watanabe ◽  
Ryuzi Katoh
Keyword(s):  
Electronic Structure ◽  
Excited State ◽  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy

Investigation of ultrafast excited state dynamics of 2,2′,4,4′,6,6′-hexanitrostilbene using femtosecond transient absorption spectroscopy

RSC Advances ◽  
2014 ◽  
Vol 4 (104) ◽  
pp. 60382-60385 ◽  
Author(s):  
Genbai Chu ◽  
Min Shui ◽  
Ying Xiong ◽  
Jing Yi ◽  
Kemei Cheng ◽  
...  
Keyword(s):  
Excited State ◽  
Excited States ◽  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Excited State Dynamics ◽  
Femtosecond Transient Absorption ◽  
Femtosecond Transient Absorption Spectroscopy

A study on the dynamics and structures of the excited states of 2,2′,4,4′,6,6′-hexanitrostilbene shows equilibrium between vibrationally hot S1 (S*1) and S1 states with lifetimes of 0.8 and 6 ps, respectively.

Excited state dynamics of symmetric and asymmetric Cr3(dpa)4Cl2 measured using femtosecond transient absorption spectroscopy

2017 ◽  
Vol 19 (37) ◽  
pp. 25471-25477 ◽  
Author(s):  
Chao-Han Cheng ◽  
Wen-Zhen Wang ◽  
Shie-Ming Peng ◽  
I-Chia Chen
Keyword(s):  
Excited State ◽  
Excited States ◽  
Metal Atom ◽  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Chain Complex ◽  
Transient Absorption Spectroscopy ◽  
Femtosecond Transient Absorption ◽  
Femtosecond Transient Absorption Spectroscopy ◽  
Atom Chain

Relaxation pathway of excited states in extended metal atom chain complex Cr3(dpa)4Cl2.

scholarly journals Dark states of symmetric polymethine dyes revealed by pump–dump–probe spectroscopy

2019 ◽  
Vol 58 (4) ◽  
Author(s):  
Kipras Redeckas ◽  
Vladislava Voiciuk ◽  
Alexander A. Ishchenko ◽  
Mikas Vengris
Keyword(s):  
Excited State ◽  
Excited States ◽  
Transient Absorption ◽  
Dynamic Equilibrium ◽  
Global Analysis ◽  
Transient Absorption Spectroscopy ◽  
Polymethine Dyes ◽  
Comprehensive Picture ◽  
Transient Data ◽  
Probe Spectroscopy

We have applied three-pulse transient absorption spectroscopy to investigate the ultrafast photoisomerization dynamics in two symmetric polymethine dyes. Pump–deplete–probe experiments have revealed that the excited state manifold of these molecules contains two closely lying excited states in the dynamic equilibrium. One of these states is emissive, while the other is largely dark. It is the dark state that ultimately results in the photoisomer formation and is the main channel of excited state decay in these dyes. We have shown that excited state populations do flow between these two states and therefore it can be inferred that the photoisomerization pathway is not predetermined by ground state distortions of the molecular structure. The decision whether the molecule will isomerize or not seems to be taken in the excited state. Global analysis of three-pulse transient data allowed us to determine the spectra of the excited and ground intermediate states and build a comprehensive picture of photoinduced dynamics in symmetric polymethine dyes.

On the Photoabsorption by Permanganate Ions in Vacuo and the Role of a Single Water Molecule. New Experimental Benchmarks for Electronic Structure Theory

ChemPhysChem ◽  
2013 ◽  
Vol 14 (6) ◽  
pp. 1133-1137 ◽  
Author(s):  
Jørgen Houmøller ◽  
Sydney H. Kaufman ◽  
Kristian Støchkel ◽  
Lokesh C. Tribedi ◽  
Steen Brøndsted Nielsen ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Water Molecule ◽  
Electronic Structure Theory ◽  
Structure Theory ◽  
Single Water Molecule

Nonthermalized excited states in Ru(II) polypyridyl complexes probed by ultrafast transient absorption spectroscopy with high photon energy excitation

2008 ◽  
Vol 86 (12) ◽  
pp. 1118-1125 ◽  
Author(s):  
Sherri A McFarland ◽  
Karen AWY Cheng ◽  
Felix S Lee ◽  
Frances L Cozens ◽  
Norman P Schepp
Keyword(s):  
Excited State ◽  
Excited States ◽  
Photon Energy ◽  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Singular Value ◽  
Transient Absorption Spectroscopy ◽  
Energy Excitation ◽  
Polypyridyl Complexes ◽  
Value Decomposition

The picosecond excited state dynamics of a series of homoleptic Ru(II) polypyridyl complexes (where LL = bpy, dmb, dmeob, dfmb, or dttb) have been investigated in aqueous solution at room temperature using femtosecond transient absorption spectroscopy with high photon energy excitation. All of the complexes studied produced similar spectroscopic signatures: a near-instantaneous bleach centered at 470–500 nm corresponding to the static absorption spectrum, as well as an intense absorption (475–650 nm) that decayed within the instrument response function (IRF) to form a broad, low-level absorption extending from 500–650 nm. Detailed analyses of both kinetic and spectral parameters by singular value decomposition (SVD) indicate that the excited state difference spectra contain contributions from at least three distinguishable species that have been assigned as ligand-based π* ← π* and ligand-to-metal-charge-transfer (LMCT) transitions concomitant with the loss of the ground state metal-to-ligand-charge-transfer (MLCT) transition. Kinetic information extracted at 530 nm (an optical marker for the fully intraligand-delocalized 3MLCT state) or 660 nm (LMCT transitions) appear to be biphasic in some cases with the amplitude of the IRF-limited component becoming larger with shorter wavelength excitation. Further, rise dynamics were observed at redder probe wavelengths for Ru(bpy)32+ and Ru(dttb)32+. These observations are different from those obtained using lower photon energy excitation and show that excitation wavelength strongly influences the early photophysical events in these Ru(II) complexes.Key words: ruthenium, photophysics, lasers, transient absorption spectroscopy, excited states, singular value decomposition (SVD).

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>

Sign in / Sign up

Export Citation Format

Share Document