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

Triplet state quenching of phenosafranine dye by indolic compounds studied by transient absorption spectroscopy

2015 ◽  
Vol 14 (2) ◽  
pp. 407-413 ◽  
Author(s):  
Martín F. Broglia ◽  
Carlos M. Previtali ◽  
Sonia G. Bertolotti
Keyword(s):  
Triplet State ◽  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Transient Absorption Spectroscopy ◽  
Synthetic Dye ◽  
Biological Relevance ◽  
Indolic Compounds

The interaction of the triplet state of the synthetic dye phenosafranine (3,7-diamino-5-phenylphenazinium chloride) with indolic compounds of biological relevance was investigated in water by means of laser flash photolysis.

scholarly journals Metal nanoparticle alters adenine induced charge transfer kinetics of vitamin K3 in magnetic field

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ranjan Kumar Behera ◽  
Abhishek Sau ◽  
Leepsa Mishra ◽  
Sankalan Mondal ◽  
Kallol Bera ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Transient Absorption ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Hydrogen Atom Transfer ◽  
Metal Nanoparticle ◽  
Transient Absorption Spectroscopy ◽  
Vitamin K3 ◽  
Time Resolved

Abstract In this article, we highlight the alterations in the photoinduced electron transfer (ET) and hydrogen atom transfer (HAT) pathways between an anti-tumor drug vitamin-K3 (MQ) and a nucleobase adenine (ADN) in the presence of gold (Au) and iron (Fe) nanoparticles (NPs). Inside the confined micellar media, with laser flash photolysis corroborated with an external magnetic field (MF), we have detected the transient geminate radicals of MQ and ADN, photo-generated through ET and HAT. We observe that the presence of AuNP on the MQ-ADN complex (AuMQ-ADN) assists HAT by limiting the ET channel, on the other hand, FeNP on the MQ-ADN complex (FeMQ-ADN) mostly favors a facile PET. We hypothesize that through selective interactions of the ADN molecules with AuNP and MQ molecules with FeNP, a preferential HAT and PET process is eased. The enhanced HAT and PET have been confirmed by the escape yields of radical intermediates by time-resolved transient absorption spectroscopy in the presence of MF.

Article

1999 ◽  
Vol 77 (5-6) ◽  
pp. 787-791
Author(s):  
Lorenzo Brancaleon ◽  
Darryl Brousmiche ◽  
Linda J Johnston
Keyword(s):  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
Transient Absorption ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Energy ◽  
Laser Flash ◽  
Transient Absorption Spectroscopy ◽  
Direct Excitation ◽  
Oxidation Potentials

The electron transfer photochemistry of 2,3-dicyanonaphthalene has been studied by a combination of fluorescence and transient absorption spectroscopy. The singlet excited state has a lifetime of 26 ns in acetonitrile and reacts with aromatic and alkene donors with oxidation potentials less than ~1.8 V with rate constants that are close to the diffusion-controlled limit. Transient absorption measurements demonstrate that the fluorescence quenching leads to efficient formation of free-radical ions. The radical ion yields have been measured for several donors and are compared to those for the more commonly used sensitizer, 1.4-dicyanonaphthalene. In the absence of added donors, direct excitation of 2,3-dicyanonaphthalene provides evidence for photoionization at high laser energy, in addition to triplet formation. The results illustrate the utility of this sensitizer for photoinduced electron transfer reactions.Key words: photoinduced electron transfer, laser flash photolysis, fluorescence, photosensitizers.

Synthesis and Characterization of Novel Platinum Acetylide Oligomers

2003 ◽  
Vol 771 ◽  
Author(s):  
Thomas M. Cooper ◽  
Benjamin C. Hall ◽  
Daniel G. McLean ◽  
Joy E. Rogers ◽  
Aaron R. Burke ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Ground State ◽  
Near Infrared ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Structure Property ◽  
Ground State Absorption ◽  
Excitation Spectra ◽  
C Nmr

AbstractAs part of an effort to develop a spectroscopic structure-property relationship in platinum acetylide oligomers, we have prepared a series of bidentate Pt(PBu3)2L2 compounds. The ligand was the series o-syd-C6H4-CΞC-(C6H4-CΞC)n-H, n = 0,1,2. The terminal oligomer unit consisted of a sydnone group ortho to the acetylene carbon. The compounds were characterized by various methods, including 13C-NMR, ground state absorption, fluorescence, phosphorescence and laser flash photolysis. The acetylenic 13C-NMR resonances showed sydnone influences that decreased with increasing number of monomer units. The ground state absorption spectra were slightly red shifted from those of the baseline oligomers not having a sydnone group. The low temperature emission and excitation spectra showed complex dependence on excitation and emission wavelengths, suggesting the chromphores resided in a distribution of solvent environments and conformations. Finally, broad triplet state absorption spectra were observed, with absorption throughout the visible and near infrared regions.

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
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