Red-edge effect in excited state reaction in β-naphthylamine

Alkaline aqueous solutions of β-naphthylamine show the edge effect; a decrease in the relative intensity or emission from the anion (RNH^?) and the neutral molecule (RNH₂) on red-edge excitation (REE) is observed. The nature of quenching of the neutral molecule by OH^? ions also changes on REE. It is suggested that on REE, participation of some non-promoting out-of-plane modes slows down the proton-transfer rate in the excited state.     

Capillary zone electrophoresis in phosphate buffer--known or unknown?

It has been shown recently that the analysis records in capillary electrophoresis may involve regions with extremely strong electromigration dispersion of peaks. Such a fundamental effect is due to the existence of more centers of symmetry in a given electrolyte system. This paper shows that even such a simple and frequently used electrolyte system as phosphate buffer may exhibit more than one center of symmetry. By using the peak shape diagram approach we have revealed that neutral and alkaline phosphate buffers have two centers of symmetry and one center of extreme dispersion. Model experiments confirmed this new important discovery.     

Buildup of the acceptor emission as a result of energy transfer from Tb3+ to Sm3+ in barium borate glass

Intensity and lifetime data indicate that the self-quenching of Sm³⁺ fluorescence in barium borate glass matrix is by direct dipole-quadrupole interactions. The quenching of Tb³⁺ fluorescence by Sm³⁺ has been found due to direct dipole-dipole interactions. However, at relatively low Sm³⁺ concentrations, energy transfer through migration among Tb³⁺ ions also occurs. Further at low Sm³⁺ concentrations, there is an enhancement of Sm³⁺ emission due to energy transfer to an Sm³⁺ that is not coupled to a second Tb³⁺ or Sm³⁺ ion. At high Sm³⁺ concentrations, no enhancement of Sm³⁺ emission occurs and is attributed to transfer to Sm³⁺Sm³⁺ or Sm³⁺Tb³⁺ couples that take up the energy by simultaneous transitions that lie well below the ${}^4\text{G}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$ manifold of Sm³⁺.     

Ferrofluid catalyzed water gas shift reaction to give carbon-dioxide and hydrogen

A ferrofluid consisting of colloidally dispersed magnetite particles in water was found to be an efficient selective catalyst for water gas shift reaction at 15–25 atmosphere of CO pressure in the temperature range of 423–553 K where the products obtained were only CO₂ and H₂. The reaction was studied as a function of variation of the concentration of catalyst, pressure of CO gas and temperature. Kinetic parameters suggested a mechanism involving first order dependence in CO and catalyst concentrations.     

Excimer emission in 9-aminoacridine hydrochloride

Excimer emission in concentrated aqueous solutions of 9-aminoacridine hydrochloride has been observed at 555 nm. A study of monomer, dimer and excimer emission, absorption and excitation spectra shows that the excited dimer emission is transformed into excimer emission at higher temperatures. Unusually large hypochromism is observed on dimer formation.     

Organotellurium chemistry : I. Synthesis,reactions and spectral characteristics of diaryltellurium diacetates

Diaryltellurium diacetates have been prepared in excellent yields by the oxidation of diaryltellurides with lead tetraacetate and also by the reaction of diaryltellurium dichlorides with silver acetate. Hydrolysis, reduction and exchange reactions of these derivatives and their spectral data are described.     

Novel inertia weight strategies for particle swarm optimization

The performance of PSO algorithm depends greatly on the appropriate parameter selection strategies for fine tuning its parameters. This paper proposes three new nonlinear strategies for selecting inertia weight which plays a significant role in particle’s foraging behaviour. The PSO variants implying these strategies are named as: fine grained inertia weight PSO (FGIWPSO); Double Exponential Self Adaptive IWPSO (DESIWPSO) and Double Exponential Dynamic IWPSO (DEDIWPSO). In FGIWPSO, inertia weight is obtained adaptively, depending on particle’s iteration wise performance and decreases exponentially. DESIWPSO and DEDIWPSO employ Gompertz function, a double exponential function for selecting inertia weight. In DESIWPSO the particles’ iteration wise performance is fed as input to the Gompertz function. On the other hand DEDIWPSO evaluates the inertia weight for whole swarm iteratively using Gompertz function where relative iteration is fed as input. The efficacy and efficiency of proposed approaches is validated on a suite of benchmark functions. The proposed variants are compared with non linear inertia weight and exponential inertia weight strategies. Experimental results assert that the proposed modifications help in improving PSO performance in terms of solution quality as well as convergence rate.