Absorption Definition and 534 Threads

Absorption spectroscopy refers to spectroscopic techniques that measure the absorption of radiation, as a function of frequency or wavelength, due to its interaction with a sample. The sample absorbs energy, i.e., photons, from the radiating field. The intensity of the absorption varies as a function of frequency, and this variation is the absorption spectrum. Absorption spectroscopy is performed across the electromagnetic spectrum.
Absorption spectroscopy is employed as an analytical chemistry tool to determine the presence of a particular substance in a sample and, in many cases, to quantify the amount of the substance present. Infrared and ultraviolet–visible spectroscopy are particularly common in analytical applications. Absorption spectroscopy is also employed in studies of molecular and atomic physics, astronomical spectroscopy and remote sensing.
There are a wide range of experimental approaches for measuring absorption spectra. The most common arrangement is to direct a generated beam of radiation at a sample and detect the intensity of the radiation that passes through it. The transmitted energy can be used to calculate the absorption. The source, sample arrangement and detection technique vary significantly depending on the frequency range and the purpose of the experiment.
Following are the major types of absorption spectroscopy:

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  1. M

    On Rayleigh Scattering and UV Light Absorption

    I've read that UV light cannot "penetrate" the atmosphere as easily during winter. But what does this exactly mean? My hypothesis is that due to rayleigh scattering, since light with smaller wave lengths scatter more, the UV light doesn't end up reaching the surface of the Earth (i.e. gets...
  2. Sandeep T S

    I Photoelectric effect questions: photon absorption and electron ejection....

    Is a photon fully absorbed by a electron in metal? Ejected electron is a free electron or bonded one? Is it possible to have a zero work function? If not why? I want to study about this detaily ,can you prefer some reference papers?
  3. YMMMA

    Confused about the number of absorption lines

    Homework Statement If an atom in energy level 1, how many absorption spectral lines can an atom exhibit due to transition between 3 levels? How about 4 and 5 levels? And also in emission? Homework Equations Concept The Attempt at a Solution I am confused one book says it can absorb a photon...
  4. X

    I Solar Spectrum: Continuous & Absorption Confusion

    Ok, I'm a bit confused with the spectrum of the Sun. Is the spectrum of the Sun continuous or absorption? Better yet, is it both? Or am I totally confusing myself? I understand that the source itself is continuous but it is partially absorbed (wrong phrasing?) as it passes through the outer...
  5. R

    Why Do Different Materials Use Different Units for the Absorption Coefficient?

    Why is the absorption coefficient (##\alpha##) of water is always given using the units ##\text{length}^{-1}##, while for other materials it is often given by ##\text{length}^{2}.\text{mass}^{-1}##? For instance, this paper uses ##cm^{-1}## for water and yet ##cm^2 / \mu g## for other...
  6. Cardinalmont

    B Why are absorption spectra continuous?

    It doesn't make sense to me that absorption spectra are (mostly) continuous. Here are my beliefs. Please tell me which piece/pieces is a/are misconception(s). 1) When light is absorbed, the energy is used to excite an electron to some discrete energy level. 2) To get to this discrete energy...
  7. T

    I Photoelectric absorption and low energy electron absorption

    I have am currently reading Radiation Detection and Measurement, by Gleen F.Knoll, and in chapter 10 page 309. And have come across something that is causing a bit of confusion, for context the chapter is on gamma ray spectroscopy. So in the text it say's 'Thus the effect of photoelectric...
  8. G

    Physics of Light/Infrared for Solar Stills Research

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  9. S

    I Gamma absorption at increasing energy levels

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  10. Rahulx084

    What Is the Concept Behind Finding Mole Fraction in Gas Absorption Problems?

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  11. Wrichik Basu

    Substances to absorb/adsorb HCHO vapours in car

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  12. R

    Calculation of absorption spectra

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  13. HastiM

    Electrons excited by absorption of a photon in Mg

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  14. S

    I Allowed infrared absorption in simple London crystals

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  15. J

    A Subtract Radiated from Background Spectrum to Analyze Absorption Spectrum

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  16. S

    I Emission lines and absorption lines

    Why more emission lines than absorption lines are usually observed in the atomic spectra of most elements hence explain why this occures?
  17. Ahmed Abdalla

    Negative absorption coefficient in muon absorption?

    Homework Statement I am conducting an experiment where I am interested in finding the absorption coefficient of different materials as muons pass through them. My data was all well until I realized more muons were measured AFTER they passed through one of the materials, which makes no sense...
  18. S

    Difference between emission due to absorption and reflection

    What is the difference between the photon interaction mechanisms in emission due to absorption and reflection?
  19. M

    I Why don't absorption and emission spectra "cancel out"?

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  20. L

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    Homework Statement i'm viewing an example written in class. it looks like this: f(x1, x2, x3, x4) = [(not x1) * x2 * x4] ∨ [x2 * x3 * x4] what should be function after applying absorption law? Homework Equations i know how another option called "gluing" works: [x1 * x2 * x3] ∨ [(not x1) *...
  21. B

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  22. E

    I Only certain emission lines show up in absorption spectrum

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  23. W

    B Light spectrum of planet Earth as seen from space

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  24. F

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  25. P

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  26. sounouhid

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  27. G

    B Why is a black surface a better emitter of IR than a silvered surface?

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  28. Z

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  29. Asamad

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  30. hilbert2

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  31. J

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  32. K

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  33. J

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  34. B

    I Absorption rate on a quantised EM field

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  35. A

    I Why is the absorption depth for GaAs more than for Germanium?

    It is based on the value of the edge coefficient I obtained, for Germanium at the wavelength of 1550 nm has a value of 459.54 / cm and GaAs at wavelength 885.6 nm has a value of 239.78 / cm. If based on the theory of absorption depth (1 / alpha), then the optimal thickness of GaAs is thicker...
  36. Timothy Schablin

    Why Does an Electron Release a Photon After Absorption?

    After an electron absorbs a photon, it will move to a higher energy state. It then releases a photon and returns to its ground state. But why does the electron release the photon? Why does it not remain in that energy state? What forces it to return to ground state?
  37. G

    Doppler effect neutron absorption

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  38. G

    Sound absorption coefficients differing with frequency

    Hi there, my understanding of absorption coefficients is that harder materials generally reflect more sound similarly to how a harder material will result a ball to bounce higher than a softer material. What I am having trouble finding research on and understanding is the reasoning behind the...
  39. W

    Get vibration frequency form absorption spectra line

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  40. F

    A Deconvolution of the optical absorption spectra

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  41. Ivanov

    I Exploring Light Absorption: What Happens When a Photon Hits an Electron?

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  42. E

    I Atmospheric Photolysis and its relation to Absorption Cross Section

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  43. S

    Lower microwave absorption efficiency to increase penetration (cooking)

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  44. H

    Acoustic Absorption Calculation: Ultrasonic Sound in Water

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  45. cdot1989

    I Photoelectric absorption versus Compton scattering

    During the photoelectric process, photons are absorbed and electrons are ejected. In Compton scattering, photons are scattered rather than absorbed. My textbook (Quantum Physics of Atoms,Molecules,Solids,Nuclei, and Particles) explains that absorption occurs in the photoelectric process because...
  46. F

    Skin temperature increase due to radiation absorption

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  47. A

    Does Scattering Involve Absorption

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  48. N

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  49. P

    Is Ammonia absorption in water exothermic?

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  50. M

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