Spectra and Decay of Trichloromethyl Radicals in Aqueous Solution

1974 ◽  
Vol 52 (7) ◽  
pp. 1135-1139 ◽  
Author(s):  
B. Lesigne ◽  
L. Gilles ◽  
R. J. Woods
Keyword(s):  
Aqueous Solution ◽  
Carbon Tetrachloride ◽  
Pulse Radiolysis ◽  
Second Order ◽  
Order Process ◽  
Second Order Process

Trichloromethyl radicals (λmax < 230 nm, ε230 nm = 2300 ± 450 M−1 cm−1) are formed by the pulse radiolysis of aqueous carbon tetrachloride solutions. At concentrations of the order of 10−4M and pH 5.5–12.4, CCl3 disappears by a second-order process with 2k = (7.4 ± 1.8) × 108 M−1 s−1 and without detectable hydrolysis. Both CCl3 and CHCl2 are believed to be formed by the pulse radiolysis of aqueous chloroform solutions but at wavelengths greater than 230 nm only absorption attributable to CCl3 was observed.

WAVELENGTH CONVERSION OF AN INFRARED SIGNAL THROUGH CASCADED SECOND-ORDER NONLINEARITY IN A LITHIUM-NIOBATE CHANNEL WAVEGUIDE

2000 ◽  
Vol 09 (01) ◽  
pp. 11-20 ◽  
Author(s):  
I. CRISTIANI ◽  
M. RINI ◽  
A. RAMPULLA ◽  
G. P. BANFI ◽  
V. DEGIORGIO
Keyword(s):  
Lithium Niobate ◽  
Pulse Energy ◽  
Wavelength Conversion ◽  
Second Order ◽  
Channel Waveguide ◽  
Phase Matching ◽  
Order Process ◽  
Pump Pulse Energy ◽  
Second Order Nonlinearity ◽  
Second Order Process

We describe a wavelength conversion experiment (generation of a pulse at the wavelength λp - Δλ from a signal at λp+Δλ under the action of a pump at λp) performed through cascaded second-order process in a lithium niobate channel waveguide. With a 58-mm-long Ti diffused channel waveguide, λp=1.1 μ m (the wavelength of phase matching for the first step of sh generation), Δλ of several nanometers and 20 ps pulse duration, wavelength conversion with unit efficiency is obtained with a pump pulse energy of the order of 102 pJ. The experimental results are successfully interpreted by making use of modal analysis and solving the appropriate nonlinear equations.

Electro-optically tunable self-focusing and self-defocusing in KTP crystals by a cascaded second-order process

2016 ◽  
Vol 14 (12) ◽  
pp. 121902-121906 ◽  
Author(s):  
Ruma Debnath Ruma Debnath ◽  
Digvijay Singh Hada Digvijay Singh Hada ◽  
Susheel Kumar Beda Susheel Kumar Beda ◽  
and Ardhendu Saha and Ardhendu Saha
Keyword(s):  
Second Order ◽  
Order Process ◽  
Self Focusing ◽  
Second Order Process

Primary Reactions during the Free Anionic Polymerization of β Nitrostyrene

1978 ◽  
Vol 33 (3) ◽  
pp. 253-256 ◽  
Author(s):  
Binh Dinh-Ngoc ◽  
Wolfram Schnabel
Keyword(s):  
Optical Absorption ◽  
Anionic Polymerization ◽  
Radical Anion ◽  
Second Order ◽  
Order Process ◽  
Solvated Electrons ◽  
Rate Laws ◽  
Species Overlap ◽  
Primary Reactions ◽  
Second Order Process

Abstractβ-Nitrostyrene (βNS) was irradiated at r. t. in solutions of hexamethylphosph. triamide (HMPT) with 50 ns pulses of 15 MeV electrons. It was found that βNS reacts with solvated electrons almost encounter controlled (k(e-solv + βNS) = (9 ± 3) · 109 l/mol s) forming the radical anion · βNS-. The optical absorption spectrum of the latter was recorded in dilute solutions ([βNS] < 5 × 10-3 mol/l). At higher βNS concentrations the formation of an additional optical absorption after the pulse in the wavelength range between 460 nm and 570 nm was detected, which is attributed to the reaction of βNS with · βNS- yielding the dimeric radical anion (· βNS-βNS-). The rate constant for this process is 4 × 107 l/mol s. At low βNS concentrations ( < 5 × 10-3 mol/l) the transient spectrum decayed by a second order process (k2 - (2.2 ± 0.5) · 109 l/mol s). This process is correlated to the neutralization of radical anions by cations formed initially. At [βNS] > 5 × 10-3 mol/l only the band at 630 nm decays according to second order kinetics. This band is correlated to the part of the anions with the highest electron density, the nitro groups. At wavelengths below 570 nm the absorptions of various species overlap. These species decay by different rate laws.

Adsorption of Zn(II) from Aqueous Solution by Attapulgite

2014 ◽  
Vol 692 ◽  
pp. 149-155 ◽  
Author(s):  
Jun Ren ◽  
Dan Xu ◽  
Ling Tao ◽  
Zhao Wen Fu
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Contact Time ◽  
Langmuir Adsorption Isotherm ◽  
Maximum Adsorption Capacity ◽  
Order Process ◽  
Langmuir Adsorption ◽  
Pseudo Second Order ◽  
Adsorbent Dose ◽  
Second Order Process

The adsorption behavior of Zn (II) by attapulgite were studied in the paper, The effects of adsorbent dose. Contact time, ionic strength and temperature on the adsorption were investigated. The maximum adsorption capacity is 4.129 mg.g-1 at 333 K. The kinetic study indicated that the adsorption was a pseudo-second-order process. The adsorption was well fitted by the Langmuir adsorption isotherm model. The results indicated that the sorption of Zn (II) by attapulgite was a spontaneous process, and the sorption was endothermic.

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