What is Absorption spectroscopy: Definition and 17 Discussions

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. L

    I How does atomic absorption spectroscopy work

    I did a prac where we tried to calculate the rydberg constant for hydrogen. We had a hydrogen lamp and we used a spectrometer that was hooked up to a photomultiplier tube to detect the wavelengths of light corresponding to the balmer series. In one section I need to write up a brief summary of...
  2. N

    Difference between absorption spectroscopy and extinction

    Hello everyone I want to know what is the difference between Absorption and Extinction spectra. and in term of experiment how can get extinction spectrum. Thank you
  3. N

    B Emission and Absorption Spectra

    When you heat things up, they emit specific wavelengths of light, right? Like when you heat up sodium, it emits yellow. But don't things emit shorter wavelengths of light at higher temperatures? Like how hotter stars are blue and colder stars are yellow. Since stars are mostly hydrogen...
  4. O

    Analysis of Atomic Absorption Spectroscopy results

    Homework Statement Hello, This week I ran an AA Spectroscopy experiment in my university, in which we had to analyze the percentage of Copper in a metal coin, and the containment of Iron in morning cereal. We used 2 standard solutions of 1 and 10 ppm (containing both Copper and Iron), and...
  5. W

    Naphthalene impurities spectroscopy

    Dear all, I was doing cleaning of naphthalene through zone refinement. After it is finished impurities from the naphthalene concentrate completely in one place of the ampule (lower part). I was interested to see which type of impurities are collected and did a spectroscopy measurement. Couple...
  6. H

    Acceptable Band Pass for a Monochromator?

    Short version: how do I figure out how much error I get when measuring light intensity vs wavelength for a given monochromator band pass width? Long version: I have a project where we will be passing white light through liquids, then looking at the spectrum intensity of the light with a...
  7. C

    Need help manipulating absorption spectroscopy data please

    Hi guys, So my project partner and I are struggling to solve a problem with our laser spectroscopy data for rubidium isotopes and I thought it may be a good idea to see if you could help us. If you take a look at the attached image you will see that the blue line shows our doppler free...
  8. G

    Help please -- Li saturation absorption spectroscopy

    Dear PF, I'm a graduate student working in an ultracold atomic phys lab. We're trying to build a new machine with Li6 as one of the components, but in order to cool it we need to do saturation absorption spectroscopy on a separate stand-alone cell in order to tell our lasers what frequencies...
  9. M

    Beer-lambert law and UV absorption spectroscopy.

    In a flash photolysis experiment, the time dependant concentration of [OH] was measured by UV absorption spectroscopy at around 308 nm, where the effective molecular absorption cross section σ = 4.13*10^-16 cm^2. Using the beer lamber law calculate the concentration (number density) of OH...
  10. L

    X-ray absorption spectroscopy - fine edge structure

    Hi, could someone tell me how the fine edge structure next the the absorbing edge in an XAS arises? from my understanding an XAS is a plot of absorption coefficient against energy of incoming xray. The absorption edge is at an energy corresponding to when the energy is just sufficient to...
  11. J

    Reflection loss during absorption spectroscopy

    An isotropic solid has a refractive index of 10 at low frequencies. A 10 um thick platelet of this solid with perfectly polished planes shows two absorption bands in optical transmission. These bands, corrected for reflection, have a (negative) Gaussian shape. They occur at frequencies of 3x1012...
  12. M

    Are there any recommended textbooks for learning absorption spectroscopy?

    Hello I am looking for a few textbooks to digest, I am learning the fundamentals of spectroscopy, in particular absorption spectroscopy of gases. Are there any great textbooks out there on these subjects? I feel I need a more solid grounding. Any undergrad would be welcome, as would any...
  13. H

    Atomic absorption spectroscopy

    hi i m studing AAS(atomic absorption specvtroscopy) technique.using beer"s law i plot a graph bw absorbance and concentration.then how can i make the quantitative analysis of my sample?
  14. C

    Atomic Absorption Spectroscopy

    Are the results of Atomic Absorption Spectroscopy affected if the metal were ions? For example, if you were trying to measure the amount of zinc in a sample but part of it was dissolved as ions and other parts were simply solid, would they measure the same absorption or would the ions not be...
  15. I

    Photoinduced absorption spectroscopy

    I'm trying to comprehend a paper I'm supposed to summarize this one: ---ok it won't let me post urls---- whatever My question, is what is the deal with photoinduced absorption spectroscopy? I gathered that it involves a "pump" (burst of light) striking the sample and then a "probe"...
  16. S

    Can I Determine Unknown Sample Concentration Using Absorption Spectroscopy?

    Hi I'm trying to measure the concentration of a sample dissolved in water. I'm using the spectrometer USB4000 which directly gives me the absorbance value. Using beer-lambert law is there a way i can determine the unknown sample concentration from this measurement? I have the values 'A' and...
  17. G

    Atomic absorption spectroscopy

    I am having major trouble trying to figure the concentration of a substance that is given by the AAS. Here's the question: To determine the iron content in a 'Milo' milk drink, a 5ml sample was diluted to 50ml. the absorption of the diluted solution and of several standard solution were...