Absorption (chemistry)

About: Absorption (chemistry) is a research topic. Over the lifetime, 18510 publications have been published within this topic receiving 358099 citations.

Adsorption Analysis: Equilibria and Kinetics

Abstract: Part 1 Equilibria: fundamentals of pure component adsorption equilibria practical approaches of pure component adsorption equilibria pure component adsorption in microporous solids multicomponent adsorption equilibria heterogeneous adsorption equilibria. Part 2 Kinetics: fundamentals of diffusion and adsorption in porous media diffusion and adsorption in porous media - Maxwell-Stefan approach analysis of adsorption kinetics in a single homogeneous particle analysis of adsorption kinetics in a zeolite particle analysis of adsorption kinetics in a heterogeneous particle. Part 3 Measurement techniques: time lag analysis in diffusion and adsorption in porous media analysis of steady state and transient diffusion cells adsorption and diffusion measurement by a chromatography method kinetics of a batch adsorber.

Gas Separation by Adsorption Processes

Abstract: Adsorbents and adsorption isotherms equilibrium adsorption of gas mixtures rate processes in adsorbers adsorber dynamics - bed profiles and breakthrough curves cyclic gas separation processes pressure-swing adsorption - principles and processes pressure-swing adsorption - models and experiments.

On the Absorption Spectra of Complex Ions II

Abstract: The secular determinants obtained in the previous paper are solved for the energy levels which are important in the absorption spectra of the normal complex ions, leaving the crystalline field strength as a parameter The values of B and C (Racah's parameters) there needed are determined from the observed spectra of free ions or in some cases by extrapolation The f -values of the transitions which connect the energy levels calculated are estimated and compared with the observed intensities The difference of the spectral width among absorption bands and lines is also considered using the energy diagram obtained Following the assignments determined by the above considerations, the calculated positions of lines and bands are rather in good agreement with the experimental data in divalent ions [MX 6 ] 2+ (M=Cr, Mn, Fe, Co, Ni), when we adjust the crystalline field parameter D q suitably In trivalent ions [MX 6 ] 3+ (M=Ti, V, Cr, Mn, Fe), it is necessary besides the adjustment of D q to use smaller values

Solvent Effects upon Fluorescence Spectra and the Dipolemoments of Excited Molecules

Abstract: A general formula for the difference of solvent shifts of fluorescence and absorption spectra in the approximation of long range dipolar interaction was derived using Ooshika’s theory of light absorption in solution. Measurements of fluorescence and absorption spectra of some naphthalene derivatives in various organic solvents were undertaken, and the data were analysed by the theoretical formula. The formula reproduces the experimental data satisfactorily, and from this fact it was concluded that the most predominant factor which determines the difference of solvent shifts of fluorescence and absorption spectra of these molecules is the interaction energy between solute and solvent molecules due to orientation polarization. The incremental values of dipolemoments in the excited state were estimated, and those for α-, β-naphthols and β-naphthyl methyl ether were interpreted as due to the increase of electron migration from the substituent in the excited state.

Alloy Formation of Gold−Silver Nanoparticles and the Dependence of the Plasmon Absorption on Their Composition

Abstract: Gold−silver alloy nanoparticles with varying mole fractions are prepared in aqueous solution by the co-reduction of chlorauric acid HAuCl4 and silver nitrate AgNO3 with sodium citrate. As the optical absorption spectra of their solutions show only one plasmon absorption it is concluded that mixing of gold and silver leads to a homogeneous formation of alloy nanoparticles. The maximum of the plasmon band blue-shifts linearly with increasing silver content. This fact cannot be explained by a simple linear combination of the dielectric constants of gold and silver within the Mie theory. On the other hand, the extinction coefficient is found to decrease exponentially rather than linearly with increasing gold mole fraction xAu. Furthermore, the size distribution of the alloy nanoparticles is examined using transmission electron microscopy (TEM). High-resolution TEM (HRTEM) also confirms the formation of homogeneous gold−silver alloy nanocrystals.