scholarly journals The pH Dependence of Absorption Spectra of Carthamin in Aqueous Solution

2007 ◽  
Vol 63 (8) ◽  
pp. 185-192
Author(s):  
Tamako Otsu ◽  
Mitsuhiko Hida
Keyword(s):  
Aqueous Solution ◽  
Absorption Spectra ◽  
Ph Dependence

Simulation of UV Absorption Spectra and Relaxation Dynamics of Uracil and Uracil-Water Clusters

2020 ◽  
Author(s):  
Branislav Milovanović ◽  
Jurica Novak ◽  
Mihajlo Etinski ◽  
Wolfgang Domcke ◽  
Nadja Doslic
Keyword(s):  
Aqueous Solution ◽  
Gas Phase ◽  
Absorption Spectra ◽  
Absorption Spectroscopy ◽  
Water Clusters ◽  
Uv Absorption ◽  
Relaxation Dynamics ◽  
Nonradiative Relaxation ◽  
Uv Absorption Spectra ◽  
Uv Absorption Spectroscopy

Despite many studies, the mechanisms of nonradiative relaxation of uracil in the gas phase and in aqueous solution are still not fully resolved. Here we combine theoretical UV absorption spectroscopy...

Visual detection of carbonate ions by inverse opal photonic crystal polymers in aqueous solution

2015 ◽  
Vol 3 (37) ◽  
pp. 9524-9527 ◽  
Author(s):  
Lu Li ◽  
Bin Zhao ◽  
Yue Long ◽  
Jin-Ming Gao ◽  
Guoqiang Yang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photonic Crystal ◽  
Polymer Films ◽  
Visual Detection ◽  
Color Change ◽  
Ph Dependence ◽  
Inverse Opal ◽  
Carbonate Ions ◽  
Crystal Polymer

This communication demonstrates a facile method to detect CO32− by naked eyes through color change based on the pH dependence of inverse opal photonic crystal polymer films.

The reduction of I2 by H2O2 in aqueous solution

2001 ◽  
Vol 79 (3) ◽  
pp. 304-311 ◽  
Author(s):  
J M Ball ◽  
J B Hnatiw
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Nuclear Reactor ◽  
Ph Dependence ◽  
Radiolysis Product ◽  
Molecular Iodine ◽  
Water Radiolysis ◽  
Reactor Accident ◽  
Rate Law ◽  
Accident Conditions

The reduction of I2 by hydrogen peroxide, a primary water radiolysis product, has been identified as a key reaction that would influence iodine volatility in nuclear reactor accident conditions (1–3). Although there have been a number of studies of the reduction of I2, there exists a great degree of controversy regarding the intermediates involved, the effect of buffers, and the general rate law (1–9). Because the rates and the mechanism of this reaction are important in predicting the pH dependence of iodine behaviour in reactor containment building after a postulated reactor accident, we have undertaken a kinetic study of I2 reduction by H2O2 in aqueous solution over a pH range of 6–9. The experiments were performed using stopped-flow instrumentation and monitoring the decay of I–3 spectrophotometrically. The effects of buffer catalysis have been examined by comparison of kinetic data obtained in sodium barbital (5,5-diethylbarbituric acid), disodium citrate, and disodium hydrogen phosphate buffers. The effect of buffers, combined with the complex acid dependence of the rate law, explains many of the discrepancies reported in earlier literature.Key words: hydrogen peroxide, molecular iodine, kinetics, iodine volatility.

Absorption spectra of pyruvic acid in water: insights from calculations for small hydrates and comparison to experiment

2020 ◽  
Vol 22 (22) ◽  
pp. 12658-12670
Author(s):  
Dorit Shemesh ◽  
Man Luo ◽  
Vicki H. Grassian ◽  
R. Benny Gerber
Keyword(s):  
Aqueous Solution ◽  
Absorption Spectra ◽  
Pyruvic Acid ◽  
Quantitative Description ◽  
Experimental Spectrum ◽  
Microscopic Interpretation

This study shows that small hydrate models including the roles of both neutral and deprotonated speciated forms provide a good quantitative description and a microscopic interpretation of the experimental spectrum of pyruvic acid in aqueous solution.

The aggregation and reaction with oxygen of the tetrasodium salt of cobalt phthalocyanine-4,4',4'',4'''-tetrasulphonic acid

1973 ◽  
Vol 26 (2) ◽  
pp. 319 ◽  
Author(s):  
LC Gruen ◽  
RJ Blagrove
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Molecular Oxygen ◽  
Absorption Spectra ◽  
Alkaline Solution ◽  
Cobalt Phthalocyanine ◽  
Visible Absorption ◽  
Reversible Addition ◽  
Dimeric Form ◽  
Low Ionic Strength

The reversible addition of molecular oxygen to the tetrasodium salt of cobalt phthalocyanine-4,4?,4?,4??-tetrasulphonic acid in aqueous solution has been confirmed. Visible absorption spectra of the monomeric and dimeric species and of the oxygen adduct have been determined. A monomer-dimer system prevails at neutral pH, low ionic strength, and low dye concentrations. The oxygen adduct and the dimeric form of the dye predominate in alkaline solution.

scholarly journals Simulating Absorption Spectra of Flavonoids in Aqueous Solution: A Polarizable QM/MM Study

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5853
Author(s):  
Sulejman Skoko ◽  
Matteo Ambrosetti ◽  
Tommaso Giovannini ◽  
Chiara Cappelli
Keyword(s):  
Molecular Dynamics ◽  
Aqueous Solution ◽  
Hydrogen Bonding ◽  
Force Field ◽  
Absorption Spectra ◽  
Computational Study ◽  
Md Simulations ◽  
Quantum Mechanical ◽  
Hydrogen Bonding Interactions

We present a detailed computational study of the UV/Vis spectra of four relevant flavonoids in aqueous solution, namely luteolin, kaempferol, quercetin, and myricetin. The absorption spectra are simulated by exploiting a fully polarizable quantum mechanical (QM)/molecular mechanics (MM) model, based on the fluctuating charge (FQ) force field. Such a model is coupled with configurational sampling obtained by performing classical molecular dynamics (MD) simulations. The calculated QM/FQ spectra are compared with the experiments. We show that an accurate reproduction of the UV/Vis spectra of the selected flavonoids can be obtained by appropriately taking into account the role of configurational sampling, polarization, and hydrogen bonding interactions.

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