scholarly journals Tunable Non-linear Refraction Properties and Ultrafast Excited State Dynamics of Dicyanomethylene Dihydrofuran Derivative

2020 ◽  
Vol 8 ◽  
Author(s):  
Linpo Yang ◽  
Zhongguo Li ◽  
Taihui Wei ◽  
Liming Zhou ◽  
Feng Li ◽  
...  
Keyword(s):  
Excited State ◽  
Transient Absorption ◽  
Refraction Index ◽  
Fast Response ◽  
Transient Absorption Spectroscopy ◽  
Relaxation Dynamics ◽  
Substantial Impact ◽  
Femtosecond Transient Absorption ◽  
Non Linear ◽  
Linear Optical

The third order non-linear optical response of a dicyanomethylene dihydrofuran compound (DCDHF-2V) was investigated using a Z-scan technique in picosecond and nanosecond time regimes. The results show that DCDHF-2V has excellent excited state non-linear refraction properties on both time regimes, and the non-linear refraction index is also solvent-dependent in the nanosecond regime. The excited state relaxation dynamics of DCDHF-2V were demystified via femtosecond transient absorption spectroscopy. The TA spectra reveal that the solvent viscosities have a substantial impact on the excited state relaxation of DCDHF-2V. The exotic photophysical phenomena in DCDHF-2V reported herein can shed new light on future development of small organic non-linear optical materials with large non-linear coefficients and fast response.

Photoinduced electron transfer dynamics in dye-sensitized ZnO nanowire photoanodes

2018 ◽  
Vol 32 (19) ◽  
pp. 1840049
Author(s):  
Akihiro Furube ◽  
Takahiro Arai ◽  
Masahiro Okazaki ◽  
Shinichiro Yanagiya ◽  
Liang-Yih Chen ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Transient Absorption ◽  
Low Cost ◽  
Transient Absorption Spectroscopy ◽  
Zno Nanowire ◽  
Dye Sensitized ◽  
Femtosecond Transient Absorption ◽  
State Formula ◽  
Flexible Solar Cell

A photoanode using dye-sensitized ZnO nanowire (NW) is a good candidate for low-cost, colorful, light-weight and flexible solar cell material. We have synthesized a ZnO NW anode and a ZnO nanowire–nanoparticle (NWNP) anode, in which ZnO nanoparticles (NPs) are decollated on the surface of NWs. Photo-induced electron transfer dynamics from the excited state of sensitizer dye (D149) to the conduction band of ZnO NW and ZnO NWNP was clarified using femtosecond transient absorption spectroscopy. The decay of the single excited state ([Formula: see text]) of D149 was faster in ZnO NW than that of ZnO NWNP, indicating that NW is more suitable as an efficient electron acceptor.

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.

Ultrafast Z → E photoisomerisation of structurally modified furylfulgides

2014 ◽  
Vol 16 (36) ◽  
pp. 19556-19563 ◽  
Author(s):  
Falk Renth ◽  
Ron Siewertsen ◽  
Frank Strübe ◽  
Jochen Mattay ◽  
Friedrich Temps
Keyword(s):  
Excited State ◽  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Chemical Modifications ◽  
Structural Motifs ◽  
Excited State Dynamics ◽  
Femtosecond Transient Absorption ◽  
Femtosecond Transient Absorption Spectroscopy

Femtosecond transient absorption spectroscopy of Z-fulgides with selected structural motifs revealed fast and direct excited-state dynamics independent of chemical modifications.

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.

Unveiling excited state energy transfer and charge transfer in a host/guest coordination cage

2018 ◽  
Vol 20 (4) ◽  
pp. 2205-2210 ◽  
Author(s):  
Rui-Ling Zhang ◽  
Yang Yang ◽  
Song-Qiu Yang ◽  
Ke-Li Han
Keyword(s):  
Energy Transfer ◽  
Excited State ◽  
State Energy ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Dynamic Processes ◽  
Excited State Energy ◽  
Femtosecond Transient Absorption ◽  
Femtosecond Transient Absorption Spectroscopy ◽  
Excited State Dynamic

Ultrafast excited-state dynamic processes, charge and energy transfer in a HGCT system are unveiled by using femtosecond transient absorption spectroscopy.

The geometry relaxation and photodeactivation from the S2 state of dibenzofuran studied by ultrafast spectroscopy

2020 ◽  
Vol 234 (7-9) ◽  
pp. 1495-1506 ◽  
Author(s):  
Lian Wang ◽  
Song Zhang ◽  
Ye Wang ◽  
Bing Zhang
Keyword(s):  
Excited State ◽  
Internal Conversion ◽  
Transient Absorption ◽  
Excited State Absorption ◽  
Transient Absorption Spectroscopy ◽  
Femtosecond Transient Absorption ◽  
Pharmaceutically Active Compound ◽  
S2 State ◽  
Franck Condon ◽  
T State

AbstractDibenzofuran (DBF) has attracted much attention from scientists recently since it is applied as a photoluminescence material and pharmaceutically active compound. Since the polychlorinated derivatives are highly toxic and manifest photostability in the environment. Femtosecond transient absorption spectroscopy associated with quantum chemical calculations are employed to investigate the ultrafast excited state dynamics of dibenzofuran from the S2 state in 1,4-dioxane and ethanol, respectively. Following excitation at a wavelength of 266 nm, the S2 state is firstly populated in the Franck–Condon region and preserves the planar molecular structure of the ground state. The observed increase of the transient absorption spectra of the excited state within the first several picoseconds indicates a geometry relaxation occurring on the S2 potential energy surface. The subsequent kinetic traces of excited state absorption show that the S2 state in the adiabatic region decays to the S1 state through a fast internal conversion, followed by intersystem crossing to the T1 state with a decay time of tens and hundreds of picoseconds in ethanol and 1,4-dioxane, respectively. Finally, the deactivation processes from the S1 or T state are slow and take place on a time scale of about 20 ns.

scholarly journals Excited State Dynamics of 7-Deazaguanosine and Guanosine 5’ Monophosphate

2021 ◽  
Author(s):  
Sarah E. Krul ◽  
Sean J. Hoehn ◽  
Karl Feierabend ◽  
Carlos Crespo-Hernández
Keyword(s):  
Excited State ◽  
Ground State ◽  
Internal Conversion ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Water Mixture ◽  
Relaxation Dynamics ◽  
Similar Time ◽  
Excited State Dynamics ◽  
Computational Calculations

<p>Minor structural modifications to the DNA and RNA nucleobases have a significant effect on their excited state dynamics and electronic relaxation pathways.<b> </b>In this study, the excited state dynamics of 7-deazaguanosine and guanosine 5’-monophosphate are investigated in aqueous and in a mixture of methanol and water using femtosecond broadband transient absorption spectroscopy following excitation at 267 nm. The transient spectra are collected using photon densities that ensure no parasitic multiphoton-induced signal from solvated electrons. The data can be fit satisfactorily using a two- or three-component kinetic model. By analyzing the results from steady-state, time-resolved, computational calculations, and the methanol-water mixture, the following general relaxation mechanism is proposed for both molecules, L<sub>b</sub> ® L<sub>a</sub> ® <sup>1</sup>ps*(ICT) ® S<sub>0</sub>, where the <sup>1</sup>ps*(ICT) stands for an intramolecular charge transfer excited singlet state with significant ps* character. In general, longer lifetimes for internal conversion are obtained for 7-deazaguanosine compared to guanosine 5’-monophosphate. Internal conversion of the <sup>1</sup>ps*(ICT) state to the ground state occurs on a similar time scale of a few picoseconds in both molecules. Collectively, the results demonstrate that substitution of a single nitrogen for a methine (C-H) group at position seven of the guanine moiety stabilizes the <sup>1</sup>pp* L<sub>b</sub> and L<sub>a</sub> states and alter the topology of their potential energy surfaces in such a way that the relaxation dynamics in 7-deazaguanosine are slowed down compared to those in guanosine 5’-monophosphate but not for the internal conversion of <sup>1</sup>ps*(ICT) state to the ground state.</p>

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