Cross section and polarization singularities in the twisted-photon absorption by atoms (Conference Presentation)

2017 ◽  
Author(s):  
Andrei Afanasev
Keyword(s):  
Cross Section ◽  
Photon Absorption

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

Bisporphyrin connected by tetrathiafulvalene

2009 ◽  
Vol 13 (01) ◽  
pp. 114-121 ◽  
Author(s):  
Kazuya Ogawa ◽  
Yasunori Nagatsuka
Keyword(s):  
Cross Section ◽  
Density Functional ◽  
Polar Solvent ◽  
Soret Band ◽  
Oxidation Potential ◽  
Time Dependent ◽  
Photon Absorption ◽  
Functional Theory ◽  
Two Photon Absorption ◽  
Two Photon

A new porphyrintetrathiafulvalene composite, where two porphyrins are bridged by te trathiafulvalene (TTF) using acetylene bonds was synthesized. The Q-band of the monomeric porphyrin appears at 590 nm whereas that of the composite is red-shifted to 620 nm and intensified. The Soret band is also red-shifted from 427 nm to 435 nm and much broadened, indicating the expansion of π-conjugation over the porphyrin and tetrathiafulvalene units. The HOMOs and LUMOs were calculated using time-dependent density functional theory. Voltammetric experiments revealed that the first oxidation potential of the TTF moiety in the composite was shifted by +155 mV compa red with TTF in the absence of composite. The effective two-photon absorption (2PA) cross section values were measured by using a nanosecond open aperture Z-scan method. The maximum effective 2PA cross section values were obtained at 760 nm, as 7300 GM in benzonitrile and 5900 GM in toluene. The values obtained in the polar solvent were 1.2 to 1.5 times larger than those in the nonpolar solvent.

scholarly journals Quantitative description of MLCT transitions in ruthenium polypyridyl complexes probed by two-photon absorption spectroscopy

2018 ◽  
Vol 190 ◽  
pp. 03012
Author(s):  
Charles W. Stark ◽  
M. Rammo ◽  
K. Petritšenko ◽  
J. Pahapill ◽  
A. Mikhaylov ◽  
...  
Keyword(s):  
Cross Section ◽  
Quantitative Description ◽  
Photon Absorption ◽  
Charge Transfer Transition ◽  
Ruthenium Polypyridyl ◽  
Polypyridyl Complexes ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Ligand Charge Transfer ◽  
Ruthenium Polypyridyl Complexes

Quantitative two-photon absorption (2PA) cross section and 2PA spectrum measurements were used to determine the molecular electric dipole change in the metal-to-ligand charge-transfer transition of ruthenium(II) tris-complexes of 2,2’-bipyridine ([Ru(bpy)3]2+) and 1,10-phenanthroline ([Ru(phen)3]2+) in several solvents.

scholarly journals INVESTIGATION OF THE 16O(γ, p)3H3α REACTION AT THE ENERGIES BELOW THE MESON PRODUCTION THRESHOLD

2021 ◽  
pp. 68-71
Author(s):  
S.N. Afanasiev
Keyword(s):  
Kinetic Energy ◽  
Cross Section ◽  
Meson Production ◽  
Diffusion Chamber ◽  
Relative Energy ◽  
Photon Absorption ◽  
Average Kinetic Energy ◽  
Bremsstrahlung Photons ◽  
Mechanism Of Interaction ◽  
The Cross

The reaction 16O(γ, p)3H3 induced by bremsstrahlung photons of endpoint energy Emaxγ = 150 MeV has been studied by the method of a diffusion chamber in a magnetic field. The energy dependence of the total cross section has been measured in the energy range from the threshold and has been founded a broad resonance centered at 55 MeV. The rate of decrease in the cross section undergoes a change in the region around 55 MeV. A comparison was made with the cross section for reactions 4He(γ, p)3H and 12С(γ, р)3H2. The agreement between the shapes of distributions for the (γ, p)3H reactions is evident and was concluded that the mechanism of interaction of the γ-quantum with the nucleus is similar. The dependence of average kinetic energy of particles on the total kinetic energy was determined. In the whole energy interval, the distribution for a proton is more than the statistical distribution. Distribution of relative energy of the proton and 3H nucleus in their c.m.s. does not agree with the predictions of the mechanism of photon absorption by an α-particle cluster, but at energies above the maximum, it agrees with calculations within the framework of the quasi-deuteron model of photoabsorption.

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.

A small-molecule with a large two-photon absorption cross-section serves as a membrane-permeable ribonucleic acid (RNA) probe for live cell imaging

2018 ◽  
Vol 42 (17) ◽  
pp. 14325-14331 ◽  
Author(s):  
Ruiqing Feng ◽  
Longlong Li ◽  
Bing Li ◽  
Jinhui Li ◽  
Dan Peng ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Live Cell Imaging ◽  
Plasma Membranes ◽  
Cell Imaging ◽  
Photon Absorption ◽  
Absorption Cross ◽  
High Permeability ◽  
Two Photon Absorption ◽  
Two Photon

DMI could light up the RNA of the nucleus and the cytoplasm in living systems, which not only exhibits larger two-photon absorption cross-sections (981 GM), but also displays high-permeability to plasma membranes of vigorous cells.

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.

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