Ahmad Yekta

Photoluminescence methods for evaluation of solubilization parameters and dynamics or micellar aggregates. Limiting cases which allow estimation of partition coefficients, aggregation numbers, entrance and exit rates

Abstract Poisson statistics is a nature consequence of a distribution of solubilized molecules among micellar aggregates. With postulates of non-cooperativity and thermodynamic considerations, relationships for extent of solute fractionation between the micellar phase and the aqueous phase are derived, as are expressions for the handling of experimental data from the quenching of photoluminescence probes of micellar aggregates.

DYNAMICS OF MOLECULAR OXYGEN IN MICELLAR SOLUTIONS

Abstract Fluorescence quenching by molecular oxygen has been employed to estimate dynamic parameters and solubility characteristics of molecular oxygen in micelle forming detergent solutions. A kinetic model which assumes that oxygen quenching occurs only in the micellar phase is employed to analyze the data.

Photoluminescence probes of micelle systems. Cyclic azoalkanes as quenchers of 1,5-dimethylnaphthalene fluorescence

Abstract Quenching of the fluorescence of detergent solutions of 1,5-dimethylnaphthalene by a series of bicyclic azoalkanes has been investigated. A model is employed which postulates that the azo quenchers are partitioned between the aqueous phase and micelles.

Kinetische und spektroskopische Untersuchung einer Quantenkettenreaktion

man Triplett-Löscher aus dem System aus, so greift 3A das Substrat 1 an unter Rückbildung von 3A mit einer Effizienz < 1,0. Diese selbstsensibilisierte Zersetzung läuft nach einem Quantenkettenmechanismus ab. Die Kettenlänge n, Effizienz und Quantenausbeute wird bestimmt durch Untersuchung der Kinetik der Thermolyse, der Quantenausbeute der Photolyse, der Intensität der Phosphoreszenz und der Energieübertragung auf Triplett-Löscher.

A search for steric effects on the rate constant for exothermic singlet-singlet electronic energy transfer in fluid solution☆

Abstract A study of exchange singlet-singlet energy transfer was made between a series of sterically hindered ketones and α-diketones in fluid cyclohexane. The comparison of the measured rate constants of energy transfer shows them to be nearly diffusion controlled and insensitive to steric hindrance. This is argued to be a solvent cage effect. That is, the rate of energy transfer in a bimolecular collision may be sensitive to steric hindrance, but the many collisions within the cage result in a transfer efficiency of unity.

USEFUL PHOTOLUMINESCENCE PROBES OF MICELLAR SYSTEMS—CYCLIC AZOALKANES AS FLUORESCENCE ACCEPTORS AND 1,5-DIMETHYLNAPHTHALENE AS A FLUORESCENCE DONOR

Abstract— Certain cyclic azoalkanes are shown to exhibit substantial fluorescence intensity and attractive absorption parameters in detergent solutions. Quenching of the fluorescence of detergent solutions of 1,5‐dimethylnaphthalene by these bicyclic azoalkanes has been investigated and is found to provide a useful system to study properties of micellar systems.