This paper reports optical absorption and luminescence studies of Cr"-doped silicate glasses with compositions chosen to vary the octahedral crystal-field splitting at the Cr" site. The extensive site-to-site disorder in the glasses is signalled by the inhomogeneous broadening of radiative transitions and by non-exponential fluorescence decay patterns. Laser-excited luminescence shows that the octahedral crystal-field splitting Dq varies between the different sites occupied by Cr" ions. Both R-line and vz+ 'Az emissions are inhomogeneously broadened by site-to-site disorder. Fluorescence line narrowing (FLN) of the R line gives a particularly dramatic demonstration of the site multiplicity. Measurement of the width of the FLN component of the R line as a function of temperature has been used to probe the density of two-level vibrational systems coupled to the electronic levels of the C+ ion

This paper reports spectroscopic studies of Cr'* ions in Auorozirconate. fluoride, borate and telluride glasses in which the average strength of the octahedral crystal field Dq/ B varies from 1.6 to 2.4. The emission spectra are shown to be inhomogeneously broadened by disorder. Non-exponential decay of the emission intensity following pulsed excitation is another signature of the extensive disorder in these glasses. The large density of states of two-level systems is shown to account for the larger-than-expected homogeneous width of the R line in lithium borate and potassium borate glasses.

No abstract

No abstract

The fluorescence spectroscopy (FS) is increasingly used in petroleum technology due the availability of better optical detection techniques, because FS offers high sensitivity, good diagnostic potential, and relatively simple instrumentation. Absorption and fluorescence spectrum of crude oil was studied at room temperature using optical path cuvette 1 cm. In this work, the absorption spectra were scanned (190-1100) nm while the emission spectra were obtained at different excitation wavelengths (266, 337, 420, and 488) nm. Crude oil was diluted by absolute ethanol to prepare different concentrations of crude oil. Ethanol as a solvent was used to dilute crude oil to obtain a solution transparent and the light could be transmitted. This work considers as an additional spectroscopic tool to develop into a fast responsive system for charchtrize the crude oil.