What is Broadening: Definition and 29 Discussions

A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules. These "fingerprints" can be compared to the previously collected "fingerprints" of atoms and molecules, and are thus used to identify the atomic and molecular components of stars and planets, which would otherwise be impossible.

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  1. M

    I Power Broadening: Explained & Resources

    Hello! I have seen mentioned in several papers the concept of power broadening, which (if I understand it right) means that the linewidth of a transition (say, in an atom) get wider with increasing the power of the laser used (even if the linewidth of the laser is kept constant). I am not...
  2. dRic2

    I Nuclear Doppler broadening of resonances

    Hi, absorption cross section in resonance depends on the relative speed of neutron and nucleus in Center of Mass frame. As you can see here https://www.nuclear-power.net/glossary/doppler-broadening/ Temperature plays a big role in determining resonance absorption cross. I don't understand why...
  3. A

    The effect of instrumental broadening on FWHM in Raman peaks

    I would like to know how to extract the instrumental broadening effect in Raman spectrometer using solid angle of the objectives, slit width or spectrometer length. I am calculation the FWHM in Raman peaks and I would like to know the effect of instrumental broadening on Raman line width and how...
  4. Leggit9

    What is the equation for calculating crystal length using index of refraction?

    Hey, The question sounds like this: I have 100 fs 400 nm pulse passing through the CaF2 crystal. After passing, it gets twice wider (200 ps). What is the length of the crystal? Can anyone share the equation which would help me to calculate this? Thank you in advance!
  5. snatchingthepi

    A Doppler Broadening in Gen 4 Nuclear Power

    I was reading about the new pebble bed gas-cooled reactor China is building and was looking into how the fuel design reduces the risk of meltdown. Apparently this is largely due to something called "Doppler Broadening" and this somehow affects neutron absorption. I don't see how this works and...
  6. Isomorphism

    On the definition of width in Doppler broadening problems.

    The following question has stumped me. I am not getting the answer marked. Instead I am getting option a). I have produced my attempt below. Also I have no idea which formula to use when the question says Doppler width. Since frequencies form a distribution, there are multiple notions of width...
  7. B

    Ultrasound spectral broadening

    Hi, I am slightly confused about the causes of spectral broadening and reverse flow in duplex ultrasound so wanted to clarify if I am correct. Here is my understanding. Is it correct? - Spectral broadening typically occurs in areas of parabolic laminar flow, distrurbed flow or turbulent flow...
  8. MrPhoenix

    Tunneling with broadening of energy levels

    Dear all, I was wondering about the problem of calculating the probability that an electron will tunnel through a certain barrier (let's assume it is a constant value). Problem is that the initial and final energies of the electron are fixed and possesses a certain broadening (for example...
  9. U

    Exponentially damped dipole - line broadening

    For an EM wave close to the transition frequency ##\omega_{21}##, we assume the dipole moment to be exponentially damped and oscillating: p(t) = p(0) e^{-\frac{\gamma}{2}t} cos(\omega_0 t) Why do we expect the electric field to be proportional to ##\dot p##? Taken from my lecturer notes on...
  10. S

    Spectrum broadening and conservation of energy?

    So, this is something I've never understood in detail. If an excited system decays and emits a photon, the lifetime of the decay will broaden the spectrum of the photon right? Basically just a Fourier transform of the "shape" of the emission in time to get the frequency components of the...
  11. C

    X-Ray Diffraction peak width due to micro-strain

    I understand that the peak-width of diffraction data increases with increasing amounts of heterogeneous, localized (AKA "micro-") strain. So, if you have a single crystal with atomic impurities in it that each create micro-strain in the lattice, you would expect the amount of peak-broadening...
  12. A

    Broadening of emission peak - "red/blue spike"

    As I understand, spectral emission peak can broaden due to high temperature of the emitter. For example, emission of "cold" CO2 will have a thin peak at 4.3um while the CO2 emitted from a (very hot) rocket plume will have a broad emission at ~4um - 4.7um (called "red/blue spike") What is the...
  13. C

    Physical explanation for power broadening

    I have been looking into broadening mechanisms and I'm stuck at trying to provide a physical explanation for power broadening. I get how the math shows that at high intenseties the decay rate goes through the roof due to saturation, but how does this increased decay rate manifest in a spread of...
  14. C

    Level Broadening at interfaces

    Dear all, I have a question regarding electronic transport in a device with length smaller than the phase relaxation length. Consider a coherent device with an interface in the middle. The interface would act as a scatterer and the electron distribution across the interface would be...
  15. G

    Natural broadening of lithium sub-levels

    Homework Statement In the 2p state of lithium, two fine structure components are formed due to spin-orbit interaction. They produce wavelengths of 670.960nm and 670.975nm. Compare Doppler and natural broadening at 700K. The lifetime of the 2p state is 27ns and \frac{\Delta \lambda}{\lambda} ~=...
  16. Y

    Instrumental line broadening of Rigaku smartlab

    Hi every one! I want to know the instrumental line broadening of Rigaku smartlab diffractrometer. I have searched out but i could not find any refrence. Please help me Thanks and best regards
  17. M

    Understanding Landau Level Broadening in Magnetic Fields

    what is meant by landau level broadening in a magnetic field?
  18. V

    Estimating Width of 21cm Line from Atomic Hydrogen Cloud

    Homework Statement Estimate the width of a 21cm spectral line produced by an interstellar cloud of atomic hydrogen with a temperature of 300K. Homework Equations From wiki (link below), I found an equation for full width at half maximum, relating it to Boltzmann constant...
  19. A

    Temperature from Doppler Effect spectral broadening

    Homework Statement A doppler effect problem: A sodium atom is emitting radiation at a wavelength of 6000 angstroms. When measured however the wavelength is widened to 6000 +/- 0.02 angstams. If this is primarily due to the doppler effect, what is the temperature of the sodium atom...
  20. N

    What is self and air broadening effects?

    What is self and air broadening effects? I have read that they appear in atmospheric modelling. Is this pressure broadening?
  21. bcrowell

    Thermal Doppler broadening in the Mossbauer effect?

    There's something I don't understand about the Mossbauer effect. I understand that the Mossbauer effect has a mechanism for eliminating the energy shift due to the recoil of the nucleus, since the inertia can be the inertia of the lattice over-all, rather than the inertia of the individual...
  22. C

    Laser Broadening: Impact on Wavelengths

    In Quantum mechanics lectures we are learning that several factors influence the wavelength produced from a laser. These factors include doppler broadening of moving atoms in the laser, the uncertainty of the transition energy levels themselves due to the uncertainty principle, etc. Previously...
  23. E

    Problem with Doppler Broadening

    Hello, I would like to know how to calculate the broadening of the spectral lines caused by the Doppler effect for the Lyman, Balmer and Paschen series. To be more concrete, I would like to know the broadening of the alpha transitions. The equations I use are the following but i don't know if...
  24. H

    Non Zeeman spectrum broadening in magnetic field

    Hi Is there any other effect than the Zeeman effect that can broaden a spectral line in a magnetic field? /Johan
  25. H_man

    Confusion about Homogenous Broadening in Lasers

    In the book I am currently reading one of the causes stated for homogenous broadening in lasers is the ".. finite lifetime of the emitting state". Now this really confuses me because I would have thought that that a change in the time it takes for this spontaneous emission should affect the...
  26. C

    Applying Lorentzian Broadening in Electron Energy Loss Spectroscopy

    I am predominantly a chemist researching electron energy loss spectroscopy, though have recently expressed some interest in spectral modelling. An area that perplexes me somewhat is applying broadening to a spectrum . For example, if I calculate a spectrum such that: Energy Intensity 0...
  27. S

    How to Calculate Doppler Broadening & Spectrographic Resolution for HII Regions

    how much is a nebular line widened by the doppler broadening due to thermal motion of gas particles? What is the spectrographic resolution required to resolve the line? I do not understand how to solve this problem. I've been given specific numbers of an HII region. How do I find the...
  28. J

    2D Electrons in Out-of-Plane Magnetic Field: DOS & Collision Broadening

    Does anyone have a link for the derivation of the density of states for 2D electrons in an out of plane magnetic field, which also details collision broadening leading to the oscillatory density of states?
  29. B

    What is the expression for the spectrum of a hot gas with Doppler broadening?

    Hi, A very hot gas is enclosed in an oven with a small window. The gas molecules emits radiation at a characteristic wavelength. I assume that because of the thermal motion of the molecules the emitted wavelengths will form a spectrum of some kind (Doppler broadening.) I am trying to derive...
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