Infrared Radiation
Infrared Radiation - Related Videos
08:17
Dynamic Lung Tumor Tracking for Stereotactic Ablative Body Radiation Therapy
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Cited by 9 •
2015
Stereotactic ablative body radiation therapy (SBRT) involves the precise delivery of high-dose radiation to cancer tumor targets. A novel SBRT platform offers a first-of-its-kind gimbaled radiation accelerator mounted within a pivoting O-ring gantry capable of dynamic image-guided tumor tracking. Here, we describe dynamic tumor tracking for lung targets.
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.
02:59
Biological Effects of Radiation
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2020
All radioactive nuclides emit high-energy particles or electromagnetic waves. When this radiation encounters living cells, it can cause heating, break chemical bonds, or ionize molecules. The most serious biological damage results when these radioactive emissions fragment or ionize molecules. For example, α and β particles emitted from nuclear decay reactions possess much higher energies than ordinary chemical bond energies. When these particles strike and penetrate matter, they produce ions...
09:38
Characterizing Far-infrared Laser Emissions and the Measurement of Their Frequencies
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Cited by 4 •
2015
We describe the generation of far-infrared radiation using an optically pumped molecular laser along with the measurement of their frequencies with heterodyne techniques. The experimental system and techniques are demonstrated using difluoromethane (CH2F2) as the laser medium whose results include three new laser emissions and eight measured laser frequencies.
02:35
A Near-Infrared Photoimmunotherapy Technique to Treat Lung Cancer in a Murine Model
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2025
This video demonstrates a near-infrared photoimmunotherapy technique to treat lung cancer in an engineered mouse model exhibiting luciferase-expressing tumor cells. Upon injecting an antibody-photosensitizer conjugate (APC) that binds to specific antigens on the tumor cells, the mouse is exposed to near-infrared radiation, inducing photochemical changes in the APC and leading to necrotic death of the bound tumor cells. The effectiveness of the treatment is monitored by injecting luciferin, a...
FAQs
A molecule absorbs infrared energy at frequencies that match its allowed vibrational motions. The masses of the bonded atoms and the chemical environment surrounding each bond influence those frequencies. Consequently, chemically different bonds or the same bond in different environments can produce different spectral features, giving the pattern molecularly specific information for chemical analysis.
Stretching motions change the distance between bonded atoms, whereas bending motions change the angle between bonds. These distinct vibrational responses contribute separate features to an absorption pattern. Examining both types of motion helps chemists relate spectral signals to molecular structure rather than treating the spectrum as a single undifferentiated measurement.
Functional groups contain characteristic bonding arrangements that absorb infrared energy through particular vibrational motions. Their associated absorption features can therefore serve as structural indicators within a spectrum. By recognizing these patterns, chemists can determine which functional groups are present and use that evidence to support compound identification.
Compounds with similar elemental compositions can still have different bonding arrangements and chemical environments. Those structural differences alter the vibrational frequencies and the overall absorption pattern recorded from each sample. Comparing spectral patterns therefore provides a way to distinguish compounds using molecular structure, not composition alone.
The sample is exposed to infrared energy, and the wavelengths or frequencies it absorbs are recorded as a spectrum. Chemists then interpret the resulting pattern by relating its features to molecular vibrations, functional groups, and bonding environments. This workflow converts a sample’s interaction with radiation into evidence about composition and structure.
Infrared measurements are useful when a reaction causes changes in bonding or molecular structure. Recording absorption patterns during the study allows chemists to look for changes associated with functional groups or other vibrational features. The technique can therefore support reaction characterization and help track chemical changes without consuming substantial amounts of sample.
Applications include qualitative analysis, reaction characterization, materials research, and molecular-structure studies. In qualitative analysis, absorption patterns help identify functional groups and distinguish compounds. For materials and reaction research, the same structural information can reveal chemical changes, while the limited sample consumption supports investigations where preserving the sample matters.