FINE STRUCTURE IN THE O16(γ, n)O15 YIELD CURVE

1959 ◽  
Vol 37 (12) ◽  
pp. 1357-1364 ◽  
Author(s):  
H. King ◽  
L. Katz
Keyword(s):  
Fine Structure ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Yield Curve ◽  
Photon Absorption ◽  
Experimental Techniques ◽  
Absorption Cross ◽  
Good Agreement ◽  
Near Threshold

Fine structure in the OI6(γ, n)O15 yield curve near threshold was examined using improved experimental techniques. Breaks were observed at threshold, 15.85, 16.14, 16.45, 16.74, 16.88, 17.05, 17.15, and 17.21 Mev. These energies are established to within ± 0.04 Mev. The integrated photon absorption cross section in these breaks resulting in (γ, n) reactions was found to be 0.47 ± 0.11 Mev-mb. Our results are in good agreement with the measurements of other workers.

scholarly journals Solvent effects on the three-photon absorption cross-section of a highly conjugated fluorene derivative

2006 ◽  
Vol 125 (16) ◽  
pp. 161102 ◽  
Author(s):  
Ion Cohanoschi ◽  
Kevin D. Belfield ◽  
Carlos Toro ◽  
Florencio E. Hernández
Keyword(s):  
Cross Section ◽  
Solvent Effects ◽  
Absorption Cross Section ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Fluorene Derivative

Syntheses and properties of acetylene-linked bis- and trisporphyrins toward two-photon photodynamic therapy

2007 ◽  
Vol 11 (06) ◽  
pp. 406-417 ◽  
Author(s):  
Yusuke Inaba ◽  
Kazuya Ogawa ◽  
Yoshiaki Kobuke
Keyword(s):  
Photodynamic Therapy ◽  
Cross Section ◽  
Sodium Salt ◽  
Absorption Cross Section ◽  
Water Soluble ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Two Photon Absorption ◽  
Photon Irradiation ◽  
Two Photon

Acetylene-bridged bisporphyrins and trisporphyrins having branched bulky bis(carboxylethyl)methyl meso-substituents were synthesized. These compounds showed large effective two-photon absorption cross-section values at 890 nm measured by using a nanosecond Z-scan method. Sodium salt of hydrolyzed trisporphyrins showed broad and red-shifted Q-bands over 900 nm. Two-photon absorption cross-section values of water-soluble dimers in water were similar to, or slightly larger than, those of ester forms evaluated in toluene. Furthermore, the generation of singlet oxygen upon one-photon irradiation for dimers in water was confirmed.

scholarly journals Ultrafast processes triggered by one- and two-photon excitation of a photochromic and luminescent hydrazone

2019 ◽  
Vol 15 ◽  
pp. 2438-2446 ◽  
Author(s):  
Alessandro Iagatti ◽  
Baihao Shao ◽  
Alberto Credi ◽  
Barbara Ventura ◽  
Ivan Aprahamian ◽  
...  
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Transient Absorption ◽  
Solvent Polarity ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Time Resolved ◽  
Two Photon Absorption ◽  
Two Photon

In this work we apply a combination of steady state and time resolved luminescence and absorption spectroscopies to investigate the excited-state dynamics of a recently developed molecular photoswitch, belonging to the hydrazone family. The outstanding properties of this molecule, involving fluorescence toggling, bistability, high isomerization quantum yield and non-negligible two-photon absorption cross section, make it very promising for numerous applications. Here we show that the light induced Z/E isomerization occurs on a fast <1 ps timescale in both toluene and acetonitrile, while the excited state lifetime of the Z-form depends on solvent polarity, suggesting a partial charge transfer nature of its low lying excited state. Time-resolved luminescence measurements evidence the presence of a main emission component in the 500–520 nm spectral range, attributed to the Z-isomer, and a very short living blue-shifted emission, attributed to the E-isomer. Finally, transient absorption measurements performed upon far-red excitation are employed as an alternative method to determine the two-photon absorption cross-section of the molecule.

Diazobenzene chromophore-doped silica films with large two-photon absorption cross-section

2009 ◽  
Vol 82 (2) ◽  
pp. 204-208 ◽  
Author(s):  
Jiangtian Li ◽  
Jianlin Shi ◽  
Zhiwei Dong ◽  
Shixiong Qian ◽  
Chenyang Wei
Keyword(s):  
Cross Section ◽  
Absorption Cross Section ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Silica Films ◽  
Two Photon Absorption ◽  
Two Photon

Syntheses and nonlinear absorption properties of conjugated porphyrin supramolecules

2007 ◽  
Vol 11 (05) ◽  
pp. 359-367 ◽  
Author(s):  
Kazuya Ogawa ◽  
Chihiro Hara ◽  
Yoshiaki Kobuke
Keyword(s):  
Cross Section ◽  
Communication System ◽  
Absorption Cross Section ◽  
Enhancement Factor ◽  
Electronic Communication ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Absorption Properties ◽  
Two Photon Absorption ◽  
Two Photon

Self-assemblies consisting of acetylene-linked bisporphyrins with a 4-nitrophenylethynyl substituent and with a phenylethynyl substituent were synthesized. The Q-band of the phenylethynyl-substituted compound appears at 762 nm whereas that of the 4-nitrophenylethynyl-substituted one was red-shifted to 784 nm and intensified. This may be attributed to the participation of the nitro group in the π-electronic communication system. HOMOs and LUMOs were calculated for these compounds using an INDO/S-CI method. The effective two-photon absorption cross-section values of these self-assemblies were measured by using a nanosecond open aperture Z-scan method. The maximum effective two-photon absorption cross-section values of 4-nitrophenylethynyl- and phenylethynyl-substituted bisporphyrins were obtained as 1.2 × 105 GM and 8.1 × 104 GM , respectively, at 890 nm. A 1.5 enhancement factor was obtained by introducing nitro groups, which was similar to the value previously reported for ferrocene- and fullerene-connected supramolecular porphyrin.

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