scholarly journals Theory of Time-resolved Photon Absorption by Molecules after Radiationless Transition. Application to Benzene after S2\ightsquigarrowS0

1984 ◽  
Vol 57 (10) ◽  
pp. 2947-2953
Author(s):  
Yuichi Fujimura ◽  
Minoru Arai ◽  
Nobuaki Nakashima ◽  
Keitaro Yoshihara
Keyword(s):  
Photon Absorption ◽  
Radiationless Transition ◽  
Time Resolved

scholarly journals Two-Photon Time-Gated In Vivo Imaging of Dihydrolipoic-Acid-Decorated Gold Nanoclusters

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7744
Author(s):  
Ye Tian ◽  
Ming Wei ◽  
Lijun Wang ◽  
Yuankai Hong ◽  
Dan Luo ◽  
...  
Keyword(s):  
In Vivo Imaging ◽  
Gold Nanoclusters ◽  
Photon Absorption ◽  
Gold Nanocluster ◽  
Time Resolved ◽  
Dihydrolipoic Acid ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Time Resolved Imaging

Due to the unique advantages of two-photon technology and time-resolved imaging technology in the biomedical field, attention has been paid to them. Gold clusters possess excellent physicochemical properties and low biotoxicity, which make them greatly advantageous in biological imaging, especially for in vivo animal imaging. A gold nanocluster was coupled with dihydrolipoic acid to obtain a functionalized nanoprobe; the material displayed significant features, including a large two-photon absorption cross-section (up to 1.59 × 105 GM) and prolonged fluorescence lifetime (>300 ns). The two-photon and time-resolution techniques were used to perform cell imaging and in vivo imaging.

scholarly journals Ultrafast processes triggered by one- and two-photon excitation of a photochromic and luminescent hydrazone

2019 ◽  
Vol 15 ◽  
pp. 2438-2446 ◽  
Author(s):  
Alessandro Iagatti ◽  
Baihao Shao ◽  
Alberto Credi ◽  
Barbara Ventura ◽  
Ivan Aprahamian ◽  
...  
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Transient Absorption ◽  
Solvent Polarity ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Time Resolved ◽  
Two Photon Absorption ◽  
Two Photon

In this work we apply a combination of steady state and time resolved luminescence and absorption spectroscopies to investigate the excited-state dynamics of a recently developed molecular photoswitch, belonging to the hydrazone family. The outstanding properties of this molecule, involving fluorescence toggling, bistability, high isomerization quantum yield and non-negligible two-photon absorption cross section, make it very promising for numerous applications. Here we show that the light induced Z/E isomerization occurs on a fast <1 ps timescale in both toluene and acetonitrile, while the excited state lifetime of the Z-form depends on solvent polarity, suggesting a partial charge transfer nature of its low lying excited state. Time-resolved luminescence measurements evidence the presence of a main emission component in the 500–520 nm spectral range, attributed to the Z-isomer, and a very short living blue-shifted emission, attributed to the E-isomer. Finally, transient absorption measurements performed upon far-red excitation are employed as an alternative method to determine the two-photon absorption cross-section of the molecule.

Ultrafast pump-probe and time-resolved fluorescence anisotropy study of the intramolecular interaction of branched styryl derivatives based on 1,3,5-triazine

2019 ◽  
Vol 28 (01) ◽  
pp. 1950003 ◽  
Author(s):  
Yaochuan Wang ◽  
Yizhuo Wang ◽  
Guiqiu Wang ◽  
Dajun Liu
Keyword(s):  
Fluorescence Anisotropy ◽  
Intramolecular Interaction ◽  
Intramolecular Interactions ◽  
Photon Absorption ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Pump Probe ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Property Measurement

A series of branched styryl derivatives based on 1,3,5-triazine were studied by nonlinear optical property measurement, degenerated pump-probe, and time-resolved fluorescence anisotropy methods to elucidate the two-photon absorption (TPA) properties and intramolecular interactions between branches. Significant enhancement of the TPA cross-section was observed in multi-branched derivatives. The anisotropy of multi-branched compounds shows faster decay and small residual values, indicating strong intramolecular interactions between branches, which further confirmed the TPA enhancement mechanism.

Pulsewidth dependence of time‐resolved two‐photon absorption with picosecond pump–probe excitation

1992 ◽  
Vol 71 (5) ◽  
pp. 2102-2105 ◽  
Author(s):  
Yasuo Tomita ◽  
Masa‐aki Shibata ◽  
Johan Bergquist
Keyword(s):  
Photon Absorption ◽  
Time Resolved ◽  
Pump Probe ◽  
Two Photon Absorption ◽  
Two Photon

scholarly journals Structural photoactivation of a full-length bacterial phytochrome

2016 ◽  
Vol 2 (8) ◽  
pp. e1600920 ◽  
Author(s):  
Alexander Björling ◽  
Oskar Berntsson ◽  
Heli Lehtivuori ◽  
Heikki Takala ◽  
Ashley J. Hughes ◽  
...  
Keyword(s):  
Time Scales ◽  
Conformational Changes ◽  
Structural Changes ◽  
Deinococcus Radiodurans ◽  
Full Length ◽  
Photon Absorption ◽  
Signaling Mechanism ◽  
Time Resolved ◽  
Binding Domains ◽  
Sensor Proteins

Phytochromes are light sensor proteins found in plants, bacteria, and fungi. They function by converting a photon absorption event into a conformational signal that propagates from the chromophore through the entire protein. However, the structure of the photoactivated state and the conformational changes that lead to it are not known. We report time-resolved x-ray scattering of the full-length phytochrome from Deinococcus radiodurans on micro- and millisecond time scales. We identify a twist of the histidine kinase output domains with respect to the chromophore-binding domains as the dominant change between the photoactivated and resting states. The time-resolved data further show that the structural changes up to the microsecond time scales are small and localized in the chromophore-binding domains. The global structural change occurs within a few milliseconds, coinciding with the formation of the spectroscopic meta-Rc state. Our findings establish key elements of the signaling mechanism of full-length bacterial phytochromes.

Picosecond Time-Resolved Resonant Two-Photon Absorption in Cu2O

1980 ◽  
pp. 294-297
Author(s):  
A. Migus ◽  
J. L. Martin ◽  
R. Astier ◽  
A. Antonetti ◽  
D. Hulin ◽  
...  
Keyword(s):  
Photon Absorption ◽  
Time Resolved ◽  
Two Photon Absorption ◽  
Two Photon

scholarly journals Two-Photon Absorption and Time-Resolved Stimulated Emission Depletion Spectroscopy of a New Fluorenyl Derivative

ChemPhysChem ◽  
2012 ◽  
Vol 13 (15) ◽  
pp. 3481-3491 ◽  
Author(s):  
Kevin D. Belfield ◽  
Mykhailo V. Bondar ◽  
Alma R. Morales ◽  
Xiling Yue ◽  
Gheorghe Luchita ◽  
...  
Keyword(s):  
Stimulated Emission ◽  
Photon Absorption ◽  
Time Resolved ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Stimulated Emission Depletion
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