The different mechanisms proposed for the spin lattice relaxation process of a paramagnetic impurity in ionic crystals are briefly summarized. The decay characteristics of the pyrazine phosphorescence in cyclohexane and benzene matrices at 1.6K and its temperature dependence can best be explained if competition between the spin lattice relaxation process between the triplet sublevels and the ra...

We describe a novel method for making instantaneous, quantitative, planar measurements of fluid mixed at the molecular level in gaseous flows. The method relies on the effective oxygen quenching of the phosphorescence of luminescent tracers, such as acetone and biacetyl. The tracer’s fluorescence emission is used to obtain information about the passive scalar, regardless of its molecular mixing...

The energy levels and lifetimes of the lowest excited triplet (T1) states of UV-B absorbers, 2-ethylhexyl salicylate (EHS) and homomenthyl salicylate (HMS), and their deprotonated anions (EHS(-) and HMS(-)) were determined through measurements of phosphorescence and electron paramagnetic resonance (EPR) spectra in rigid solutions at 77 K. The observed T1 energies of EHS and HMS are higher than ...

Polycyclic aromatic thiophenes (thiaarenes) ex­ hibit vibronically well-resolved phosphorescence spectra in rigid matrices (e.g. ethanol at 77 K). Al­ though several papers on the properties of the lowest triplet (T,) states o f thiophene benzologs have appeared in the literature [1 -5 ] , no systematic study on the relationship between the T } state ener­ gies (phosphorescence 0 . 0 bands) of ...

Abs ract : A unique method is described in the present paper for quantitative mapping of temperature field in a liquid flow by taking advantage of the phosphorescence lifetime dependence on temperature. This methodology represents an extension of the Molecular Tagging Velocimetry (MTV) technique. As in MTV measurements, the phosphorescence signal is imaged at two successive times within the lif...

The rational design and syntheses of a new series of Os(II) complexes with formula [Os(fppz)(2)(CO)(L)] (1: L=4-dimethylaminopyridine; 2: L = pyridine; 3: L = 4,4'-bipyridine; 4: L = pyridazine; 5: L = 4-cyanopyridine), bearing two (2-pyridyl)pyrazolate ligands (fppz) together with one carbonyl and one N-heterocyclic ligand at the axial positions are reported. Single-crystal X-ray diffraction s...

Fluorescence and phosphorescence are listed as mineral optical–physical properties in classical gemology textbooks. The trace elements which exist gems, certain defects the crystal lattice, some luminous molecules contribute to luminescence phenomena gem materials, including fluorescence phosphorescence. A systematic study using an excitation-emission matrix (EEM) not only provides detailed inf...

Asymmetrically substituted perylene imide derivatives PIa and PIx display phosphorescence in glassy matrices at 77 K. The lifetime is 49.0 ms for PIa and 13.5 ms for PIx. The triplet energy is 1.79 eV for PIa and 1.68 eV for PIx as confirmed by sensitization experiments of the C(60) triplet.