Fluorescence quenching of 22 polycyclic aromatic hydrocarbons by nitromethane in toluene and acetonitrile solutions has been studied. Contrary to Sawicki's observations that the fluorescence of hydrocarbons with the fluoranthene skeleton is not quenched that of 11J2and 3.4-benzofluoranthene and fluoranthene itself is quenched. These compounds have a high energy of the fluorescence transition. T...

Luminescence quenching of [Ru(diphenyl-bpr)3]Cl2 and of [Ru(diphenyl-phen)3]Cl2 by 19 transition metal complexes is reported. These complexes have properties which permit them to supplement the widely used [Ru9bpy)3] 2+ and [Ru(phen)3] 2+ sensitizers. The excited state of these complexes can also be tuned significantly by solvent variation. Quenching is predominantly by diffusion. Decay times, ...

Illumination of dark-adapted barley plants with low light transiently induced a large nonphotochemical quenching of chlorophyll fluorescence. This reaction was identified as a form of high-energy-state quenching. Its appearance was not accompanied by zeaxanthin synthesis but was associated with a reversible inactivation of a fraction of photosystem II (PSII) centers. Both the fluorescence quenc...

Fluorescence quenching method providing information about the structure and dynamics of proteins, ligand-protein and protein-lipid interactions was used in a study of the rat ovarian LH/hCG receptor. The efficiency of two different quenchers, acrylamide and iodide, was tested. Acrylamide was significantly more effective in quenching of intrinsic fluorescence of ovarian membranes than iodide and...

Structural conformation of proteins can be determined using spectroscopic measurements. Fluorescence activity of proteins is one of the primary criterions for studying biophysical characteristics. Structural elucidation of proteins is important for drug developments.Fluorescence quenching of Cytochrome C, Myoglobin and Leghemoglobin were carried out using acrylamide and Potassium Iodide (KI) so...

The ̄uorescence quenching rate constants of pyrene monomer and excimer by CH3I were obtained at several temperatures in methylcyclohexane. Both quenching processes are kinetically controlled, allowing insight on the mechanism of quenching. The rate constants have both temperature-independent and temperature-dependent components. The temperature-independent component for both monomer and excimer...

By combining a high frequency modulation system for measurement of fluorescence with a phosphoroscope type apparatus for measurement of luminescence, recordings of fluorescence and luminescence induction kinetics under identical conditions were obtained. Both measuring sys­ tems tolerated the application of saturating pulses of white light for rapid, transient elimination of photochemical quenc...

Cast aluminum alloys are usually subject to solution treatment, quenching, and aging hardening for improved mechanical properties. Cooling rate during quenching plays an important role in residual stress, distortion, and mechanical property distributions in the resultant cast aluminum components. As the cooling rates of work pieces heavily depend on the interfacial heat transfer coefficient (HT...