Back to ASDL
-
To download the media (or a link to the media) in these blog posts simply right click on the illustrations, animations, photos, or video and save to your computer.
Unless otherwise identified, all images are available under the following Creative Commons License.
.
Tag Archives: spectroscopy
Instrumentation for Turbidimetry and Nephelometry
Turbidimetry and nephelometry are two techniques based on the elastic scattering of radiation by a suspension of colloidal particles: (a) in turbidimetry the detector is placed in line with the source and the decrease in the radiation’s transmitted power is … Continue reading
Posted in Illustration
Tagged instrument, nephelometry, scattering, spectroscopy, turbidimetry
Leave a comment
Elastic Scattering of Light From Particles
Elastic scattering is divided into two types: Rayleigh, or small-particle scattering, and large-particle scattering. Rayleigh scattering occurs when the scattering particle’s largest dimension is less than 5% of the radiation’s wavelength. The intensity of the scattered radiation is proportional to … Continue reading
Self-Absorption in Flame Emission Spectroscopy
Flame emission is subject to the same types of chemical interferences as atomic absorption. These interferences are minimized by adjusting the flame’s composition and adding protecting agents, releasing agents, or ionization suppressors. An additional chemical interference results from self-absorption. Because … Continue reading
Posted in Illustration
Tagged emission, flame emission, interference, self-absorption, spectroscopy
Leave a comment
Background Corrections in Emission Spectroscopy
The most important spectral interference in emission spectroscopy is broad, background emission from the flame or plasma, and emission bands from molecular species. This background emission is particularly severe for flames because the temperature is insufficient to break down refractory … Continue reading
Posted in Illustration
Tagged background correction, emission, flame emission, ICP, spectroscopy
Leave a comment
Inductively Coupled Plasma Torch
The illustration below provides a schematic diagram of an inductively coupled plasma source (ICP), which consists of three concentric quartz tubes surrounded at the top by a radio-frequency induction coil. The sample is mixed with a stream of Ar using … Continue reading
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
Posted in Illustration
Tagged photoluminescence, sampling volume, slit, spectroscopy
Leave a comment
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
Posted in Uncategorized
Tagged fluorescence, fluorimeter, instrument, phosphorescence, photoluminescence, spectrofluorimeter, spectroscopy
Leave a comment
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
Posted in Illustration
Tagged emission, fluorescence, photoluminescence, spectroscopy
Leave a comment
Pathways for Deactivating an Excited State Without Emission
Shown here is an illustration of the energy level diagram for a molecule exhibiting pathways for the deactivation of an excited state: vr is vibrational relaxation; ic is internal conversion; ec is external conversion; and isc is an intersystem crossing. … Continue reading