Direct Observation of Ultrafast Excimer Formation in Covalent Perylenediimide Dimers Using Near-Infrared Transient Absorption Spectroscopy

2014 ◽  
Vol 5 (15) ◽  
pp. 2588-2593 ◽  
Author(s):  
Kristen E. Brown ◽  
Walter A. Salamant ◽  
Leah E. Shoer ◽  
Ryan M. Young ◽  
Michael R. Wasielewski
Keyword(s):  
Absorption Spectroscopy ◽  
Direct Observation ◽  
Near Infrared ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Excimer Formation

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 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 Infrared and near infrared transient absorption spectroscopy of molecular free radicals

1993 ◽  
Author(s):  
T.J. Sears ◽  
M. Wu ◽  
G.E. Hall ◽  
B.C. Chang ◽  
G. Hansford ◽  
...  
Keyword(s):  
Free Radicals ◽  
Absorption Spectroscopy ◽  
Near Infrared ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy

Absorption spectroscopy of singlet CH2 near 11 200 cm–1

2001 ◽  
Vol 79 (2-3) ◽  
pp. 347-358 ◽  
Author(s):  
K Kobayashi ◽  
T J Sears
Keyword(s):  
Absorption Spectroscopy ◽  
Near Infrared ◽  
Transient Absorption ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Energy Levels ◽  
Zero Point ◽  
Laser Flash ◽  
Infrared Region ◽  
Transient Absorption Spectroscopy

New spectra of methylene, CH2, in the near infrared region of the singlet band system have been obtained. They were detected by laser transient absorption spectroscopy following excimer laser flash photolysis of ketene, CH2CO, at 308 nm. The new data provide information on the nature and energies of rotational levels in three vibronic states that lie between approximately 11 500 and 13 000 cm–1 above the zero point level of the lower, ã1A1, state. Taken together with previous measurements, a fairly complete picture of the vibronic energy levels of CH2 in this region can be built up. There is generally good agreement with the recent computational studies on the singlet states of CH2, but some evidence for discrepancies for levels with K = 3 and higher near the minimum of the [Formula: see text]1B1 potential surface. PACS No.: 33.20Ea

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.

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