Clocking the buildup dynamics of light-induced states through attosecond transient absorption spectrum

2021 ◽  
Author(s):  
Xiaoxia Wu ◽  
Shaofeng Zhang ◽  
Difa Ye
Keyword(s):  
Floquet Theory ◽  
Transient Absorption ◽  
Scaling Law ◽  
Time Lag ◽  
Time Dependent ◽  
Transient Absorption Spectroscopy ◽  
Transient Absorption Spectrum ◽  
Wide Range ◽  
Maximal Shift ◽  
Buildup Time

Abstract The buildup processes of the light-induced states (LISs) in attosecond transient absorption spectroscopy are studied by solving the time-dependent Schrödinger equation and compared with the quasistatic Floquet theory, revealing a time lag of the maximal shift and strongest absorbance of the LIS with respect to the zero delay that is referred to as the buildup time. We analytically derive a scaling law for the buildup time that confirms the numerical results over a wide range of detunings. Our theory verifies the commonly accepted scenario of nearly instantaneous response of matter to light if the pump field is blue-detuned, but some differences are found in the near-resonant and red-detuning cases. Implications of the buildup time in petahertz optoelectronics are discussed.

scholarly journals Mechanistic Investigations of an α-Aminoarylation Photoredox Reaction

2021 ◽  
Author(s):  
Bernard Stevenson ◽  
Ethan Spielvogel ◽  
Emily Loiaconi ◽  
Victor M. Wambua ◽  
Roman Nakhamiyayev ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Absorption Spectroscopy ◽  
Rate Constant ◽  
Kinetic Modeling ◽  
Rate Constants ◽  
Transient Absorption ◽  
Coupling Reaction ◽  
Time Dependent ◽  
Transient Absorption Spectroscopy ◽  
Mechanistic Investigations

We present time-dependent percent and quantum yield measurements of a photoredox-catalyzed coupling reaction between 1,4-dicyanobenzene and N-phenylpyrrolidine. We also use transient absorption spectroscopy to examine the kinetics within the reaction and use kinetic modeling to extract rate constants and predict how changes in rate constant will impact the quantum yield.

scholarly journals Excited state dynamics for visible-light sensitization of a photochromic benzil-subsituted phenoxyl-imidazolyl radical

2019 ◽  
Vol 15 ◽  
pp. 2369-2379
Author(s):  
Yoichi Kobayashi ◽  
Yukie Mamiya ◽  
Katsuya Mutoh ◽  
Hikaru Sotome ◽  
Masafumi Koga ◽  
...  
Keyword(s):  
Visible Light ◽  
Rational Design ◽  
Materials Science ◽  
Transient Absorption ◽  
Life Sciences ◽  
Transient Absorption Spectroscopy ◽  
Back Reaction ◽  
Switching Speed ◽  
Wide Range ◽  
Potential Applications

Visible-light sensitized photoswitches have been paid particular attention in the fields of life sciences and materials science because long-wavelength light reduces photodegradation, transmits deep inside of matters, and achieves the selective excitation in condensed systems. Among various photoswitch molecules, the phenoxyl-imidazolyl radical complex (PIC) is a recently developed thermally reversible photochromic molecule whose thermal back reaction can be tuned from tens of nanoseconds to tens of seconds by rational design of the molecular structure. While the wide range of tunability of the switching speed of PIC opened up various potential applications, no photosensitivity to visible light limits its applications. In this study, we synthesized a visible-light sensitized PIC derivative conjugated with a benzil unit. Femtosecond transient absorption spectroscopy revealed that the benzil unit acts as a singlet photosensitizer for PIC by the Dexter-type energy transfer. Visible-light sensitized photochromic reactions of PIC are important for expanding the versatility of potential applications to life sciences and materials science.

scholarly journals Excited State Dynamics for Visible Light Sensitization of Fast Photochromic Phenoxyl-Imidazolyl Radical Complex with Aryl Ketone

2019 ◽  
Author(s):  
Yoichi Kobayashi ◽  
Yukie Mamiya ◽  
Katsuya Mutoh ◽  
Hikaru Sotome ◽  
Masafumi Koga ◽  
...  
Keyword(s):  
Visible Light ◽  
Life Science ◽  
Materials Science ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Back Reaction ◽  
Switching Speed ◽  
Radical Complex ◽  
Wide Range ◽  
Potential Applications

Visible light sensitized photoswitches have been paid particular attention in the fields of life science and materials science because long-wavelength light reduces photodegradation, transmits deep inside of matters, and achieves the selective excitation in condensed systems.Among various photoswitch molecules, phenoxyl-imidazolyl radical complex (PIC) is a recently developed thermally-reversible photochromic molecule whose thermal back reaction can be tuned from tens of nanoseconds to tens of seconds by rational designs of the molecular structure. While the wide range of tunability of the switching speed of PIC opened up various potential applications, no photosensitivity to visible light limits its applications. In this study, we synthesized a visible light sensitized PIC derivative conjugated with a benzil unit. Femtosecond transient absorption spectroscopy revealed that the benzil unit acts as a singlet photosensitizer for PIC by the Dexter-type energy transfer. Visible light sensitized photochromic reactions of PIC are important for expanding the versatility of potential applications to life science and material science.

scholarly journals Nanosecond photochromic molecular switching of a biphenyl-bridged imidazole dimer revealed by wide range transient absorption spectroscopy

2015 ◽  
Vol 51 (7) ◽  
pp. 1375-1378 ◽  
Author(s):  
Tetsuo Yamaguchi ◽  
Michiel F. Hilbers ◽  
Paul P. Reinders ◽  
Yoichi Kobayashi ◽  
Albert M. Brouwer ◽  
...  
Keyword(s):  
Time Constant ◽  
Absorption Spectroscopy ◽  
Recovery Time ◽  
Transient Absorption ◽  
Thermal Recovery ◽  
Transient Absorption Spectroscopy ◽  
Back Reaction ◽  
Molecular Switching ◽  
Wide Range

We demonstrate that a biphenyl-bridged imidazole dimer exhibits fast photochromism with a thermal recovery time constant of ∼100 ns, which is the fastest thermal back reaction in all reported imidazole dimers.

Buildup time of Autler-Townes splitting in attosecond transient absorption spectroscopy

2021 ◽  
Vol 103 (6) ◽  
Author(s):  
Xiaoxia Wu ◽  
Zengqiang Yang ◽  
Shaofeng Zhang ◽  
Xinwen Ma ◽  
Jie Liu ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Buildup Time

scholarly journals Picosecond Flash Photolysis of Photochromic Spiropyrans

1984 ◽  
Vol 4 (1-6) ◽  
pp. 129-138 ◽  
Author(s):  
S. A. Krysanov ◽  
M. V. Alfimov
Keyword(s):  
Room Temperature ◽  
Internal Conversion ◽  
Transient Absorption ◽  
Flash Photolysis ◽  
Decay Channel ◽  
Transient Absorption Spectrum ◽  
Colored Form ◽  
Pyran Ring ◽  
Decay Times ◽  
Buildup Time

The transient species involved in photocoloration and photobleaching of indoline 6-nitrosubstituted spiropyran solutions at room temperature were studied by picosecond flash photolysis. Transient absorption spectrum of spiropyran colorless form consists of two bands peaked at 440 and 585 nm and is assigned to the photoinduced intermediate non-planar cis configuration with the breaked C—O bond of the pyran ring. This transient is found to have the buildup time shorter than 10 ps and initial decay times of about 10 ns in benzene and 5 ns in ethanol. The colored form exhibits the transient absorption peaked at 460 nm with the lifetime of about 200 ps in ethanol which is assigned to Sn ← S1 absorption of colored form. The predominant decay channel of the colored form S1 state is shown to be internal conversion S1 ⇝ S0 with the quantum yield of about 0.70 ± 0.15.

scholarly journals Mechanistic Investigations of an α-Aminoarylation Photoredox Reaction

2020 ◽  
Author(s):  
Bernard Stevenson ◽  
Ethan Spielvogel ◽  
Emily Loiaconi ◽  
Victor M. Wambua ◽  
Roman Nakhamiyayev ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Absorption Spectroscopy ◽  
Rate Constant ◽  
Kinetic Modeling ◽  
Rate Constants ◽  
Transient Absorption ◽  
Coupling Reaction ◽  
Time Dependent ◽  
Transient Absorption Spectroscopy ◽  
Mechanistic Investigations

We present time-dependent percent and quantum yield measurements of a photoredox-catalyzed coupling reaction between 1,4-dicyanobenzene and N-phenylpyrrolidine. We also use transient absorption spectroscopy to examine the kinetics within the reaction and use kinetic modeling to extract rate constants and predict how changes in rate constant will impact the quantum yield.

scholarly journals Small Polaron Hopping in Fe:LiNbO3 as a Function of Temperature and Composition

Crystals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 294 ◽  
Author(s):  
Laura Vittadello ◽  
Marco Bazzan ◽  
Simon Messerschmidt ◽  
Mirco Imlau
Keyword(s):  
Charge Transport ◽  
Transient Absorption ◽  
Small Polaron ◽  
Transient Absorption Spectroscopy ◽  
Relaxation Dynamics ◽  
Experimental Conditions ◽  
Polaron Hopping ◽  
Small Polaron Hopping ◽  
Wide Range ◽  
Temperature Ranges

Small-polaron hopping involved in charge transport in Fe-doped congruent lithium niobate is investigated as a function of temperature and composition by means of light-induced transient absorption spectroscopy. The relaxation dynamics of the light-induced polaron population is characterized by individual activation energies within different temperature ranges. A numerical investigation carried out by Monte Carlo simulations reveals that these findings may be understood in terms of the varying abundance of the different types of hops that the polarons may perform among regular or defective lattice sites. The role of the temperature and of the sample composition on the distribution of the different hop types is thus explored for a wide range of parameters, allowing one to preview the charge transport properties for a given set of experimental conditions.

scholarly journals Mechanistic Investigations of an α-Aminoarylation Photoredox Reaction

2020 ◽  
Author(s):  
Bernard Stevenson ◽  
Ethan Spielvogel ◽  
Emily Loiaconi ◽  
Victor M. Wambua ◽  
Roman Nakhamiyayev ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Absorption Spectroscopy ◽  
Rate Constant ◽  
Kinetic Modeling ◽  
Rate Constants ◽  
Transient Absorption ◽  
Coupling Reaction ◽  
Time Dependent ◽  
Transient Absorption Spectroscopy ◽  
Mechanistic Investigations

We present time-dependent percent and quantum yield measurements of a photoredox-catalyzed coupling reaction between 1,4-dicyanobenzene and N-phenylpyrrolidine. We also use transient absorption spectroscopy to examine the kinetics within the reaction and use kinetic modeling to extract rate constants and predict how changes in rate constant will impact the quantum yield.

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