Exploring the ultrafast dynamics of a diarylethene derivative using sub-10 fs laser pulses

2019 ◽  
Vol 21 (1) ◽  
pp. 192-204 ◽  
Author(s):  
Arkadiusz Jarota ◽  
Ewa Pastorczak ◽  
Walid Tawfik ◽  
Bing Xue ◽  
Rafał Kania ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Ring Opening ◽  
Internal Conversion ◽  
Laser Pulses ◽  
Ultrafast Dynamics ◽  
Ring Opening Reaction ◽  
Fs Laser

The fast internal conversion S1 → S0 of a diarylethenes photoswitch, facilitated by two vibrational stretching modes, results in a low quantum yield of the ring-opening reaction.

scholarly journals ULTRAFAST DYNAMICS OF GOLD NANORODS: TUNING BETWEEN PHOTO-BLEACHING AND PHOTO-INDUCED ABSORPTION

2011 ◽  
Vol 10 (04n05) ◽  
pp. 687-691 ◽  
Author(s):  
M. ANIJA ◽  
SUNIL KUMAR ◽  
N. KAMARAJU ◽  
NEHA TIWARI ◽  
S. K. KULKARNI ◽  
...  
Keyword(s):  
Gold Nanorods ◽  
Colloidal Suspensions ◽  
Laser Pulses ◽  
Pump Intensity ◽  
Ultrafast Dynamics ◽  
Laser Photon ◽  
Induced Absorption ◽  
Plasmon Peak ◽  
Fs Laser ◽  
The Difference

We report ultrafast electron dynamics in gold nanorods investigated using 80 fs laser pulses centered at 1.57 eV. Five types of nanorod colloidal suspensions in water having their longitudinal surface plasmon peak (E LSP ) on either side of the laser photon energy (EL) have been studied. For E LSP > EL, photo-induced absorption with single decay time constant is observed. On the other hand, for E LSP < EL, photo-bleaching is observed having bi-exponential decay dynamics; the faster one between 1–3 ps and slower one between 7 ps to 22 ps both of them increasing almost linearly with the difference |EL – E LSP |. These time constants increase linearly with the pump intensity. Simulations have been carried out to understand the interplay between photo-bleaching and photo-induced absorption.

Ultrafast dynamics of hemin aggregates

2017 ◽  
Vol 19 (39) ◽  
pp. 26862-26869 ◽  
Author(s):  
Arpita Nath ◽  
J. A. Dharmadhikari ◽  
A. K. Dharmadhikari ◽  
D. Mathur ◽  
S. Mazumdar
Keyword(s):  
Kerr Effect ◽  
Laser Pulses ◽  
Optical Kerr Effect ◽  
Ultrafast Dynamics ◽  
Time Resolved ◽  
Central Wavelength ◽  
Fs Laser

The effects of solvents on the conformation of hemin leading to ultrafast libration process have been probed using the time-resolved optical Kerr effect (OKE) with 35 fs laser pulses (at a central wavelength of 800 nm).

Ultrafast dynamics and temperature effects on the quantum efficiency of the ring-opening reaction of a photochromic indolylfulgide

2008 ◽  
Vol 141 (3) ◽  
pp. 137-139 ◽  
Author(s):  
Thomas Brust ◽  
Simone Draxler ◽  
Stephan Malkmus ◽  
Christine Schulz ◽  
Marc Zastrow ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
Temperature Effects ◽  
Ring Opening ◽  
Ultrafast Dynamics ◽  
Ring Opening Reaction

Nonadiabatic Dynamics Simulation of Photoinduced Ring-Opening Reaction of 2(5H)-Thiophenone with Internal Conversion and Intersystem Crossing

2021 ◽  
Author(s):  
Bin-Bin Xie ◽  
Bo Long Liu ◽  
Xiu-Fang Tang ◽  
Diandong Tang ◽  
Lin Shen ◽  
...  
Keyword(s):  
Ring Opening ◽  
Internal Conversion ◽  
Mean Field ◽  
Dynamics Simulation ◽  
Quantum Trajectory ◽  
Intersystem Crossing ◽  
Nonadiabatic Dynamics ◽  
Field Approach ◽  
Ring Opening Reaction

In the present work, the quantum trajectory mean-field approach, which is able to overcome the overcoherence problem, was generalized to simulate internal conversion and intersystem crossing processes simultaneously. The photoinduced...

On the Conrotatory Ring Opening of 3-Carbomethoxycyclobutene Vis-À-Vis 3-Carbomethoxy-1,2-Benzocyclobutene and the Predominant Inward Opening of 3-Dimethylaminocarbonyl-1,2-Benzocyclobutene

2018 ◽  
Author(s):  
Veejendra Yadav ◽  
Dasari L V K Prasad ◽  
Arpita Yadav ◽  
Maddali L N Rao
Keyword(s):  
Transition State ◽  
Ring Opening ◽  
Electron Process ◽  
Ring Opening Reaction ◽  
Stable Species ◽  
Electron Event

<p>The torquoselectivity of conrotatory ring opening of 3-carbomethoxycyclobutene is controlled by p<sub>C1C2</sub>→s*<sub>C3C4</sub> and s<sub>C3C4</sub>→p*<sub>CO</sub> interactions in the transition state in a 4-electron process as opposed to only s<sub>C3C4</sub>→p*<sub>CO</sub> interaction in an apparently 8-electron event in 3-carbomethoxy-1,2-benzocyclobutene. The ring opening of 3-carbomethoxy-1,2-benzocyclobutene is sufficiently endothermic. We therefore argue that the reverse ring closing reaction is faster than the forward ring opening reaction and, thus, it establishes an equilibrium between the two and subsequently allows formation of the more stable species <i>via</i> outward ring opening reaction. Application of this argument to 3-dimethylaminocarbonyl-1,2-benzocyclobutene explains the predominantly observed inward opening.</p>

scholarly journals Laser-induced thermal grating spectroscopy based on femtosecond laser multi-photon absorption

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maria Ruchkina ◽  
Dina Hot ◽  
Pengji Ding ◽  
Ali Hosseinnia ◽  
Per-Erik Bengtsson ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Laser Pulses ◽  
Photon Absorption ◽  
Gas Flows ◽  
Single Shot ◽  
Photon Excitation ◽  
Fs Laser ◽  
Thermal Grating ◽  
Grating Spectroscopy ◽  
First Time

AbstractLaser-induced grating spectroscopy (LIGS) is for the first time explored in a configuration based on the crossing of two focused femtosecond (fs) laser pulses (800-nm wavelength) and a focused continuous-wave (cw) laser beam (532-nm wavelength). A thermal grating was formed by multi-photon absorption of the fs-laser pulses by $$\hbox {N}_{{2}}$$ N 2 with a pulse energy around 700 $$\upmu $$ μ J ($$\sim $$ ∼ 45 TW/$$\hbox {cm}^{2}$$ cm 2 ). The feasibility of this LIGS configuration was investigated for thermometry in heated nitrogen gas flows. The temperature was varied from room temperature up to 750 K, producing strong single-shot LIGS signals. A model based on the solution of the linearized hydrodynamic equations was used to extract temperature information from single-shot experimental data, and the results show excellent agreement with the thermocouple measurements. Furthermore, the fluorescence produced by the fs-laser pulses was investigated. This study indicates an 8-photon absorption pathway for $$\hbox {N}_{{2}}$$ N 2 in order to reach the $$\hbox {B}^{3}\Pi _{g}$$ B 3 Π g state from the ground state, and 8 + 5 photon excitation to reach the $$\hbox {B}^{2}\Sigma _{u}^{+}$$ B 2 Σ u + state of the $$\hbox {N}_{2}^{+}$$ N 2 + ion. At pulse energies higher than 1 mJ, the LIGS signal was disturbed due to the generation of plasma. Additionally, measurements in argon gas and air were performed, where the LIGS signal for argon shows lower intensity compared to air and $$\hbox {N}_{{2}}$$ N 2 .

scholarly journals Expanding Monomers as Anti-Shrinkage Additives

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 806
Author(s):  
Philipp Marx ◽  
Frank Wiesbrock
Keyword(s):  
Ring Opening ◽  
Covalent Bond ◽  
Volumetric Shrinkage ◽  
Structure Property ◽  
Atomic Packing ◽  
Materials Properties ◽  
Volumetric Expansion ◽  
Structure Property Relationships ◽  
Ring Opening Reaction ◽  
Measuring Techniques

Commonly, volumetric shrinkage occurs during polymerizations due to the shortening of the equilibrium Van der Waals distance of two molecules to the length of a (significantly shorter) covalent bond. This volumetric shrinkage can have severe influence on the materials’ properties. One strategy to overcome this volumetric shrinkage is the use of expanding monomers that show volumetric expansion during polymerization reactions. Such monomers exhibit cyclic or even oligocyclic structural motifs with a correspondingly dense atomic packing. During the ring-opening reaction of such monomers, linear structures with atomic packing of lower density are formed, which results in volumetric expansion or at least reduced volumetric shrinkage. This review provides a concise overview of expanding monomers with a focus on the elucidation of structure-property relationships. Preceded by a brief introduction of measuring techniques for the quantification of volumetric changes, the most prominent classes of expanding monomers will be presented and discussed, namely cycloalkanes and cycloalkenes, oxacycles, benzoxazines, as well as thiocyclic compounds. Spiroorthoesters, spiroorthocarbonates, cyclic carbonates, and benzoxazines are particularly highlighted.

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