scholarly journals Direct Observation of the Transition-State Region in the Photodissociation of CH3I by Femtosecond Extreme Ultraviolet Transient Absorption Spectroscopy

2015 ◽  
Vol 6 (24) ◽  
pp. 5072-5077 ◽  
Author(s):  
Andrew R. Attar ◽  
Aditi Bhattacherjee ◽  
Stephen R. Leone
Keyword(s):  
Transition State ◽  
Absorption Spectroscopy ◽  
Direct Observation ◽  
Transient Absorption ◽  
Extreme Ultraviolet ◽  
Transient Absorption Spectroscopy ◽  
State Region

scholarly journals Mapping the multi-step mechanism of a photoredox catalyzed atom-transfer radical polymerization reaction by direct observation of the reactive intermediates

2020 ◽  
Vol 11 (17) ◽  
pp. 4475-4481 ◽  
Author(s):  
Luke Lewis-Borrell ◽  
Mahima Sneha ◽  
Aditi Bhattacherjee ◽  
Ian P. Clark ◽  
Andrew J. Orr-Ewing
Keyword(s):  
Atom Transfer Radical Polymerization ◽  
Real Time ◽  
Radical Polymerization ◽  
Absorption Spectroscopy ◽  
Direct Observation ◽  
Transient Absorption ◽  
Reactive Intermediates ◽  
Transient Absorption Spectroscopy ◽  
Polymerization Reaction ◽  
Step Mechanism

Short-lived intermediates are tracked in real-time by transient absorption spectroscopy during a multi-step photoredox catalysed polymerization reaction.

scholarly journals Symmetry of molecular Rydberg states revealed by XUV transient absorption spectroscopy

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Peng Peng ◽  
Claude Marceau ◽  
Marius Hervé ◽  
P. B. Corkum ◽  
A. Yu. Naumov ◽  
...  
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Extreme Ultraviolet ◽  
Rydberg States ◽  
Transient Absorption Spectroscopy ◽  
Electronic Transitions ◽  
Final States ◽  
Polarization Direction ◽  
Quasibound State

AbstractTransient absorption spectroscopy is utilized extensively for measurements of bound- and quasibound-state dynamics of atoms and molecules. The extension of this technique into the extreme ultraviolet (XUV) region with attosecond pulses has the potential to attain unprecedented time resolution. Here we apply this technique to aligned-in-space molecules. The XUV pulses are much shorter than the time during which the molecules remain aligned, typically $$<$$<100 fs. However, transient absorption is not an instantaneous probe, because long-lived coherences re-emit for picoseconds to nanoseconds. Due to dephasing of the rotational wavepacket, it is not clear if these coherences will be evident in the absorption spectrum, and whether the properties of the initial excitations will be preserved. We studied Rydberg states of N$${}_{2}$$2 and O$${}_{2}$$2 from 12 to 23 eV. We were able to determine the polarization direction of the electronic transitions, and hence identify the symmetry of the final states.

scholarly journals Tracking dissociation dynamics of strong-field ionized 1,2-dibromoethane with femtosecond XUV transient absorption spectroscopy

2016 ◽  
Vol 18 (21) ◽  
pp. 14644-14653 ◽  
Author(s):  
Adam S. Chatterley ◽  
Florian Lackner ◽  
Daniel M. Neumark ◽  
Stephen R. Leone ◽  
Oliver Gessner
Keyword(s):  
Absorption Spectroscopy ◽  
Near Infrared ◽  
Transient Absorption ◽  
Extreme Ultraviolet ◽  
Strong Field ◽  
Transient Absorption Spectroscopy ◽  
Time Resolved ◽  
Strong Field Ionization ◽  
Dissociation Dynamics ◽  
Ultraviolet Absorption Spectroscopy

Using femtosecond time-resolved extreme ultraviolet absorption spectroscopy, the dissociation dynamics of the haloalkane 1,2-dibromoethane (DBE) have been explored following strong field ionization by femtosecond near infrared pulses at intensities between 7.5 × 1013 and 2.2 × 1014 W cm−2.

scholarly journals Coupled valence carrier and core-exciton dynamics in WS2 probed by few-femtosecond extreme ultraviolet transient absorption spectroscopy

2021 ◽  
Vol 104 (6) ◽  
Author(s):  
Hung-Tzu Chang ◽  
Alexander Guggenmos ◽  
Christopher T. Chen ◽  
Juwon Oh ◽  
Romain Géneaux ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Extreme Ultraviolet ◽  
Transient Absorption Spectroscopy ◽  
Exciton Dynamics

scholarly journals Direct Observation of S2–S1 Internal Conversion in Pyrene by Femtosecond Transient Absorption

1999 ◽  
Vol 19 (1-4) ◽  
pp. 375-379 ◽  
Author(s):  
Frederik V. R. Neuwahl ◽  
Paolo Foggi
Keyword(s):  
Time Constant ◽  
Absorption Spectroscopy ◽  
Direct Observation ◽  
Internal Conversion ◽  
Transient Absorption ◽  
Conversion Process ◽  
Transient Absorption Spectroscopy ◽  
Kinetic Measurements ◽  
State Population ◽  
Femtosecond Transient Absorption

UV pulses of 100 fs at 340 nm are utilised to excite pyrene to the vibrationally cold S2 state. Population and depopulation processes occurring in the S2 state are investigated by transient absorption spectroscopy with a white continuum probe. In the first 400 fs after excitation it is possible to measure the growth and disappearance of a band at 585 nm which is assigned to the S14←S2 transition. As a consequence of the internal conversion process from S2 to S1 state, the disappearance of the 585 nm band and the growth of the transient spectrum due to Sn←S1 transitions can be observed. Kinetic measurements of the S2 decay and S1 growing signals provide an estimate of the rate of internal conversion which occurs with a time constant of 150±50 fs.

scholarly journals Direct Mapping of Curve-Crossing Dynamics in IBr by Attosecond Transient Absorption Spectroscopy

2019 ◽  
Author(s):  
Yuki Kobayashi ◽  
Kristina Chang ◽  
Tao Zeng ◽  
Daniel Neumark ◽  
Stephen Leone
Keyword(s):  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Extreme Ultraviolet ◽  
Transient Absorption Spectroscopy ◽  
Two Photon ◽  
Direct Mapping ◽  
Avoided Crossing ◽  
Iodine Monobromide ◽  
Rapid Switching ◽  
Electronic Character

<p> </p><p>The electronic character of photoexcited molecules can abruptly change at avoided crossings and conical intersections. Here, we report direct mapping of the coupled interplay between electrons and nuclei in a prototype molecule, iodine monobromide (IBr), using attosecond transient absorption spectroscopy. A few-femtosecond visible pulse resonantly excites the B(3_0+) state of IBr and the accompanying photodissociation dynamics are tracked by an attosecond extreme-ultraviolet pulse that simultaneously probes the I-4d and Br-3d corelevel absorption edges. Direct comparison with quantum mechanical simulations unambiguously identifies the core-level absorption features associated with adiabatic and diabatic channels at the B/Y avoided crossing and concurrent two-photon dissociation processes that involve the Y/Z avoided crossing. The results show clear evidence for rapid switching of valence molecularorbital occupations at the avoided crossing.</p> <p><br></p>

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