Solvent Effects on C60 Excited State Cross Sections

1994 ◽  
Vol 374 ◽  
Author(s):  
Daniel G. McLean ◽  
Donna M. Brandelik ◽  
Mark C. Brant ◽  
Richard L. Sutherland ◽  
Lynn Frock
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Cross Sections ◽  
Solvent Effects ◽  
Nonlinear Absorption ◽  
Equation System ◽  
Survey Study ◽  
Absorption Properties ◽  
Absorption Measurements ◽  
Initial Transmission

AbstractA survey study of solvent effects on the linear and nonlinear absorption properties of C60 has been done. The nonlinear absorption measurements are done at 694 nm with a Q-switched Nd:YAG pumped dye laser. In conjunction with this study a three level rate equation system has been solved analytically and the model results used to extract effective excited state cross sections. A difference and a ratio are calculated from the effective excited state cross section and the ground state cross section. The analysis demonstrates that it is this difference and the initial transmission which determine the critical fluence for the onset of nonlinear absorption. The saturation behavior is determined by the ratio of the cross sections and the initial transmission. Based on these findings C60 is shown to have some of the highest reported nonlinear absorption properties at 694 nm. The effective excited state cross sections at 694 nm are reported for the solutions and correlations to the solvent types demonstrated.

scholarly journals Nonlinear absorption properties and excited-state charge-transfer dynamics of Er doped ZnO films

2018 ◽  
Vol 8 (11) ◽  
pp. 3262 ◽  
Author(s):  
Si-Qiu Li ◽  
Cheng-Bao Yao ◽  
Yu Cai ◽  
Yue Han ◽  
Ke-Xin Zhang ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Nonlinear Absorption ◽  
Zno Films ◽  
Absorption Properties ◽  
Doped Zno ◽  
Charge Transfer Dynamics ◽  
Er Doped ◽  
State Charge

Broadband nonlinear absorption properties of two-dimensional hexagonal tellurene nanosheets

Nanoscale ◽  
2019 ◽  
Vol 11 (36) ◽  
pp. 17058-17064 ◽  
Author(s):  
Fang Zhang ◽  
Guowei Liu ◽  
Zhengping Wang ◽  
Tianhong Tang ◽  
Xinle Wang ◽  
...  
Keyword(s):  
Nonlinear Optics ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Nonlinear Absorption ◽  
Two Dimensional ◽  
Absorption Cross ◽  
Infrared Band ◽  
Absorption Properties ◽  
Potential Applications

Low saturable intensity, large TPA coefficient and the absorption cross-section demonstrate that tellurene is an advanced broadband nonlinear absorption material and has potential applications in the nonlinear optics field, especially in the infrared band.

scholarly journals Impact of the Subunit Arrangement on the Nonlinear Absorption Properties of Organometallic Complexes with Ruthenium(II) σ-Acetylide and Benzothiadiazole as Building Units §

Inorganics ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 67
Author(s):  
Eleonora Garoni ◽  
Alessia Colombo ◽  
Kenji Kamada ◽  
Claudia Dragonetti ◽  
Dominique Roberto
Keyword(s):  
Electron Acceptor ◽  
Cross Sections ◽  
Nonlinear Absorption ◽  
Organometallic Complexes ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Absorption Properties ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Resonance Enhancement

In this paper, the nonlinear absorption properties of two complexes consisting of Ru(C≡CPh)(C≡C)(dppe)2 (dppe = Ph2PCH2CH2PPh2) as electron donor (D) and 4,7-di(2-thienyl)benzo[c][1,2,5]thiadiazole as electron acceptor (A) units in two different arrangement, i.e., A–D–A and D–A–D, are presented. They were measured in solution by the femtosecond open-aperture Z-scan method. The complexes show moderate two-photon absorption cross-sections σ(2) of several hundred to one thousand GM (here 1 GM = 10−50 cm4 s molecule−1 photon−1). Although they are formed by the same building units, it was found that the two-photon absorption values of the D–A–D arrangement are six times higher than that of the A–D–A one. This difference can be explained by the number of metal cores (one or two ruthenium centers), the geometrical configurations of the complexes (more or less planar), and the resonance enhancement by lowering the intermediate state.

Erbium Doped Tellurite Glasses

1991 ◽  
Vol 244 ◽  
Author(s):  
Jau-Sheng Wang ◽  
Elias Snitzer ◽  
George H. Sigel
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Optical Transition ◽  
Emission Cross Section ◽  
Excited State Absorption ◽  
Tellurite Glasses ◽  
Ground State Absorption ◽  
Erbium Doped

ABSTRACTThe results to be presented focus on the optimization of tellurite glass compositions which are suitable both for doping with erbium oxide as well as subsequent for fiber drawing. The laser related properties, such as fluorescence spectrum, lifetime, and optical transition cross sections will be presented. Judd-Ofelt parameters for erbium in the glasses have been exploited to predict fluorescence lifetime, excited state absorption(ESA), ground state absorption(GSA) and ground state fluorescence(GSF). For comparison, the absorption cross section, emission cross section, excited state absorption(ESA)/ground state absorption(GSA)(0.8μm pumping) and fluorescence terminating in the ground state(GSF)/excited state absorption(ESA) ratios are calculated for both Al2O3-SiO2 and tellurite glasses.

Photoneutron cross sections in 7Li

1977 ◽  
Vol 55 (5) ◽  
pp. 428-433 ◽  
Author(s):  
H. Ferdinande ◽  
N. K. Sherman ◽  
K. H. Lokan ◽  
C. K. Ross
Keyword(s):  
Fine Structure ◽  
Excited State ◽  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Reasonable Agreement ◽  
Branching Ratio ◽  
Energy Spectra ◽  
Average Value ◽  
First Excited State

Photoneutron energy spectra from 7Li have been measured by time-of-flight methods, for bremsstrahlung end-point energies increasing in 2 MeV steps from 13 to 25 MeV. The ground-state and approximate first-excited-state differential cross sections at 90° have been obtained from 8.5 to 23 MeV. No pronounced fine structure has been observed. The measured branching ratio to the first excited state falls from an average value of 0.70 between 10.3 and 14.5 MeV to an average of 0.29 between 14.5 and 18 MeV, and rises again to an average of 0.38 between 18 and 23 MeV. This behaviour can be explained by a crude theoretical model in which 1p → 2s and 1p → 1d single particle transitions dominate below 18 MeV. The calculation predicts a branching ratio of 0.50 near threshold, falling to 0.23 at higher energies, in reasonable agreement with the experiment. The integrated value of the ground-state cross section up to 23 MeV is about (38.7 ± 3.9) MeV mb, while that for the first excited state is about (17.2 ± 3.4) MeV mb. Together they account for 39% of the exchange-augmented dipole sum of 7Li.

Photoneutron Reactions in 18O

1975 ◽  
Vol 53 (8) ◽  
pp. 786-794 ◽  
Author(s):  
J. D. Allan ◽  
J. W. Jury ◽  
R. G. Johnson ◽  
K. G. McNeill ◽  
J. G. Woodworth ◽  
...  
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Cross Sections ◽  
Differential Cross ◽  
Ground State ◽  
Energy Spectra ◽  
Continuum State ◽  
Average Value ◽  
First Excited State ◽  
Time Of Flight Spectroscopy

Photoneutron energy spectra from 18O have been measured by time-of-flight spectroscopy at bremsstrahlung endpoint energies from 11 to 18 MeV in 1 MeV steps to obtain the (γ, n0) and (γ, n1) differential cross sections. The ground state photoneutron cross section contains at least 8 major resonances in the region from 10 to 17 MeV and has an average value of 100 μb/sr. The cross section to the first excited state of 17O contains only two major resonances, at 11.4 and 14.4 MeV, and the average cross section in the region from 11 to 16 MeV is about 40 μb/sr. Of particular interest is a resonance at 14.4 MeV which appears to reflect a simple excitation of one of the valence neutrons to the 2p3/2 state. Analysis of the (γ, n0) and (γ, n1) cross sections for this continuum state leads to estimates of the configuration amplitudes of the 2s1/2 and 1d5/2 components of this state to be 0.62 ± 0.06 and 0.78 ± 0.08 respectively and the ratio of the (2s1/2)2 to (1d5/2)2 amplitudes in the ground state of 18O to be 0.39 ± 0.02.

Optical Limiting Characteristics of Dendrons and Dendrimers Incorporating Dithienylpolyene Moieties

1999 ◽  
Vol 597 ◽  
Author(s):  
B. Ozer ◽  
B.-S. Kang ◽  
C. W. Spangler
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Cross Sections ◽  
Excitation Cross Section ◽  
Optical Limiting ◽  
Intersystem Crossing ◽  
Radical Ions ◽  
Saturable Absorbers ◽  
The Past ◽  
Charge States

AbstractOver the past decade there has been considerable progress in the design of new chromophores for potential optical limiting applications. Most of the focus has been centered on molecules that are capable of efficient excited state absorptions whose cross-sections are larger than the original π–π* excitation cross-section, usually referred to as reverse saturable absorbers (RSAs). The vast majority of chromophores having RSA characteristics depend on efficient intersystem crossing from the excited state singlet (S1) to a highly absorbing and relatively long-lived triplet state (T1). However, much less attention has been paid to alternative excited state absorptions, particularly from charge states such as polaronic radical-ions and bipolaronic diions. In this presentation, we propose that monodisperse dendrimers based on dendron coupling to core molecules such as bisphenol A are potential optical limiting materials based on photo-generation of such charge states in the dendron-attached chromophores, such as dithienylpolyenes. The design and syntheses of these dendrons and dendrimers are presented, and the absorption characteristics of the most likely charge states discussed from an optical limiting perspective.

Wavelength dependent studies of nonlinear absorption in zinc meso-tetra(p-methoxyphenyl)tetrabenzoporphyrin (Znmp TBP) using Z-scan technique

2001 ◽  
Vol 05 (07) ◽  
pp. 549-554 ◽  
Author(s):  
N. K. M. NAGA SRINIVAS ◽  
S. VENUGOPAL RAO ◽  
D. V. G. L. N. RAO ◽  
B. K. KIMBALL ◽  
M. NAKASHIMA ◽  
...  
Keyword(s):  
Excited State ◽  
Cross Sections ◽  
Nonlinear Absorption ◽  
Visible Region ◽  
Excited State Absorption ◽  
Photon Absorption ◽  
Dispersion Data ◽  
Level Model ◽  
Scan Data ◽  
Two Photon Absorption Coefficient

We report here, our experimental results and theoretical analysis of the dispersion data of nonlinear absorption in zinc meso-tetra-(p-methoxyphenyl)tetrabenzoporphyrin (ZnmpTBP). Using a ns optical parametric oscillator (OPO) we obtain the open aperture Z-scan data over the visible region starting from 480 nm to 600 nm. We use a more general five-level model for evaluating the excited state parameters like excited state absorption coefficients, two-photon absorption coefficient, etc. Due to its large excited state absorption cross-sections this material acts as a very good candidate for a broadband optical limiter in the visible region.

Theoretical Calculation of Optical Collisional Cross Sections and α-Parameter Values for Transitions of Interest in Atomic Absorption Spectrometry

1977 ◽  
Vol 31 (5) ◽  
pp. 424-434 ◽  
Author(s):  
R. J. Lovett ◽  
M. L. Parsons
Keyword(s):  
Excited State ◽  
Hyperfine Structure ◽  
Cross Section ◽  
Cross Sections ◽  
Absorption Spectrometry ◽  
Full Width ◽  
Half Maximum ◽  
Line Broadening ◽  
Actual Shape ◽  
Parameter Values

A method has been developed for calculating optical collisional cross sections and subsequent a-parameter values for spectral transitions of interest to analytical atomic spectroscopists. A combination of classical and semiclassical line broadening theory is used. The calculated values compare well (±20% or less) with values determined experimentally for elements without extensive hyperfine structure. If hyperfine structure is significant, the calculated a-parameter can be used to calculate the full width at half maximum of the spectral transition, but not the actual shape. The cross section values are found to correlate well with the proximity of the energy of the excited state of the atom to the ionization energy and to the orbitals involved in the electronic transition (e.g., s-p). A method of converting a values to different flame conditions has also been developed. Cross sections and a-parameter values for a total of 114 transitions from 52 elements have been calculated for the air-acetylene flame.

The photoionization absorption continua for alkali metal vapours

1968 ◽  
Vol 304 (1477) ◽  
pp. 233-244 ◽  
Keyword(s):  
Alkali Metal ◽  
Cross Section ◽  
Cross Sections ◽  
Absolute Cross Section ◽  
Molecular Absorption ◽  
The Cross ◽  
Experimental Values ◽  
Existing Data ◽  
Absorption Measurements

Absorption measurements are reported for the metal vapours potassium, rubidium and caesium and existing data for lithium and sodium are reviewed. The separation of atomic and molecular absorption is discussed and the data presented as absolute cross-section curves as a function of wavelength. The shapes of the atomic photoionization continua and their absolute values are discussed in relation to existing theoretical cross-sections data. Best experimental values of the cross-sections at the series limits are found to be : Li = 1.9 ± 0.2 Mb, Na = 0.125 ± 0.01 Mb, K = 0.007 ± 0.002 Mb, Rb = 0.10 ± 0.015 Mb and Cs = 0.20 ± 0.03 Mb. The curves for potassium, rubidium and caesium have non-zero minima and that for sodium has a minimum which is near zero. Experimental minimum values of 4 ± 2 x 10 -3 Mb, 8 ± 3 x 10 -3 Mb and 6 ± 1 x 10 -2 Mb for potassium, rubidium and caesium respectively are obtained.

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