Tag Archives: photoluminescence

Effect of Slit Orientation on Emission Intensity

Illustration showing how slit orientation changes the volume from which fluorescence is measured: (a) vertical slit orientation; (b) horizontal slit orientation. Suppose each slit’s dimensions are 0.1 mm × 3 mm. In (a) the dimensions of the sampling volume are … Continue reading

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Fluorescence and Phosphorescence Instrumentation

The basic instrumentation for monitoring fluorescence and phosphorescence—a source of radiation, a means of selecting a narrow band of radiation, and a detector—are the same as those for absorption spectroscopy. The unique demands of both fluorescence and phosphorescence, however, require … Continue reading

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Fluorescence Emission Spectrum for Tyrosine

A photoluminescence spectrum is recorded by measuring emission intensity  as a function of either the excitation wavelength or the emission wavelength. An excitation spectrum is obtained by monitoring emission at a fixed wavelength while varying the excitation wavelength. When corrected … Continue reading

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Singlet and Triplet States

Photoluminescence is divided into two categories: fluorescence and phosphorescence. A pair of electrons occupying the same electronic ground state have opposite spins and are said to be in a singlet spin state; see (a) in the illustration below. When an … Continue reading

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Absorbance and Emission Spectroscopy

The illustration here is a simplified energy diagram showing the absorption and emission of a photon by an atom or a molecule. When a photon of energy hν strikes the atom or molecule, absorption may occur if the difference in energy, … Continue reading

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