Reflectance Spectroscopy
Reflectance Spectroscopy - Related Videos
06:50
Diffuse Reflectance Spectroscopy: Getting the Capillary Refill Test Under One's Thumb
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Cited by 4 •
2017
This protocol describes how the use of diffuse polarization spectroscopy can improve the clinical usefulness of the capillary refill test. We suggest a more detailed analysis of the course of the capillary refill in healthy volunteers using diffuse reflectance spectroscopy videos and new informatic endpoints.
01:13
Attenuated Total Reflectance (ATR) Infrared Spectroscopy: Overview
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2024
Attenuated total reflectance (ATR) infrared spectroscopy is a powerful analytical technique used to study the composition of materials. It is widely employed in chemistry, materials science, forensic science, and other fields where sample characterization is required. ATR has several advantages over traditional transmission IR spectroscopy, including the requirement of little to no sample preparation and the ability to analyze a wide range of samples. The ATR process begins by directing a beam...
13:59
Reflection and Refraction
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2023
Source: Derek Wilson, Asantha Cooray, PhD, Department of Physics & Astronomy, School of Physical Sciences, University of California, Irvine, CA Light travels at different speeds depending on the material through which it is propagating. When light travels from one material to another, it will either slow down or speed up. In order to conserve energy and momentum, the light must change the direction in which it propagates. This bending of light is known as refraction. Some fraction of the...
08:11
Infrared Spectroscopy
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2023
Source: Vy M. Dong and Zhiwei Chen, Department of Chemistry, University of California, Irvine, CA This experiment will demonstrate the use of infrared (IR) spectroscopy (also known as vibrational spectroscopy) to elucidate the identity of an unknown compound by identifying the functional group(s) present. IR spectra will be obtained on an IR spectrometer using the attenuated total reflection (ATR) sampling technique with a neat sample of the unknown.
09:21
Mössbauer Spectroscopy
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2023
Source: Joshua Wofford, Tamara M. Powers, Department of Chemistry, Texas A&M University Mössbauer spectroscopy is a bulk characterization technique that examines the nuclear excitation of an atom by gamma rays in the solid state. The resulting Mössbauer spectrum provides information about the oxidation state, spin state, and electronic environment around the target atom, which, in combination, gives evidence about the electronic structure and ligand arrangement (geometry) of the molecule.
FAQs
Three interactions shape the measured signal: absorption removes portions of the incident light, scattering redirects light, and surface properties influence how the sample reflects it. Their combined effect produces wavelength-dependent spectral patterns. In chemistry, interpreting those patterns matters because the signal can reveal both chemical composition and physical structure rather than representing composition alone.
Selected wavelengths determine which changes in the reflected signal become visible and therefore which spectral patterns can be compared. Measuring across wavelengths provides a profile rather than a single intensity value, allowing researchers to relate differences in the spectrum to variations in composition or physical structure. The chosen spectral coverage consequently influences the information available for characterization.
Reflectance data must be interpreted as the combined result of absorption, scattering, and surface behavior. Absorption-related changes can contribute evidence about composition, while scattering and surface properties can alter the signal in ways related to physical structure. Considering these influences together helps chemists avoid treating every spectral difference as a direct change in chemical composition.
When a sample is solid or opaque, transmitting light through it can be difficult, making a reflected-light measurement more practical. Reflectance analysis can often be performed without extensive sample preparation, which supports examination of materials that are inconvenient for transmission methods. This distinction is especially useful in chemistry when the sample's form or opacity limits transmission analysis.
A typical measurement directs incident light toward the material and records the amount reflected at selected wavelengths. The resulting wavelength-dependent signal is assembled into a spectrum, which is then examined for patterns associated with the sample. This workflow connects the physical light response to chemical or structural characterization without relying on a single reflected-light value.
Solid and opaque materials are particularly suitable when transmission measurements are difficult. Reflectance measurements can also be valuable when extensive preparation would be undesirable, because the technique can examine such samples with little preparation. These characteristics broaden chemical analysis beyond samples that can be made into convenient transmission specimens.
Spectral patterns can support compound identification, quality control, surface characterization, and monitoring of chemical changes. In research, the measurements help relate a material's reflected-light behavior to its composition or physical structure. In industrial settings, the same information can contribute to materials analysis and quality-related evaluation, particularly for solid or opaque materials.
It provides a way to follow material behavior when chemical changes alter the reflected spectrum. Monitoring those changes can complement one-time compound identification by showing how a sample's spectral pattern changes during analysis. The approach also links chemical composition with surface and physical-structure information, making it relevant to materials research, surface studies, and industrial analysis.