A spectroscopic technique typically used to determine vibrational modes of molecules (or rotational and other low-frequency modes of systems). Commonly used in chemistry to provide a structural fingerprint by which molecules can be identified.
Questions tagged [raman-spectroscopy]
98 questions
17
votes
4 answers
Why can't I see the blue color scattered by the lower atmosphere of the earth?
I understand that the blue colour of the sky is because of the scattering of blue light by molecules in earth's atmosphere. The scattering appears to be happening from molecules that are far above in the earth's atmosphere. What about the scattering…
coder
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Why are spectrums of incandescent light bulbs continuous despite the presence of Argon around them?
Incandescent bulbs emit light by heating a filament using electricity, this would lead to a continuous spectrum according to Kirchoff's first law. However, the glass casing around the filament is filled with Argon (or other inert gases), its…
Apporv
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8
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1 answer
What is a virtual state?
In quantum mechanics / Raman spectroscopy, what is a virtual state? What is the difference between a virtual state and a superposition of states? Can you simply think of the virtual state as a superposition of eigenstates?
If you have the complete…
dllahr
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7
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Quantum description of Raman effect
In the classical description of the Raman effect the object of study is the electric polarizability of the system.
I'm interested in learning the quantum description of the Raman effect and in Bernath's "Spectra of atoms and molecules" it is said…
baruffa
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Origin of Selection Rules for Rotational Raman spectra
I am aware of the fact that selection rules for transitions between two different quantum states, are obtained via an assessment of the corresponding transition matrix elements [1,2].
When we consider the spectrum of a pure rotational spectrum,…
299792458
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What is the difference between the dipole in IR and Raman vibrations?
In order for a vibration to be IR active, there must be a change in the dipole moment ($\mu$) of the molecule, which is given by:
$\mu$ = $\sum$ q * r
Where q is the charge magnitude and r is the distance between the two charges.
Now, whenever I…
Snek22
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5
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Second order spectra vs First order
Can someone explain for dummies what these are? How they are seen? And how to distinguish them? Perhaps, post some images. Thanks.
Lex Podgorny
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1 answer
Ratio between Stokes and anti-Stokes scattering amplitudes in Raman scattering
I'm trying to understand the amplitudes and the ratio between those of Stokes and anti-Stokes scattering in Raman scattering. I understand that from a Boltzmann distribution point of view, the ratio between Stokes and anti-Stokes scattering should…
4
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1 answer
Laser speckle reduction for integration time of microseconds
How to reduce laser speckle noise for an imaging system that demands integration times of microseconds? I am aware of these two commercial solutions:
Optotune laser speckle reducer. It has a frequency of 300 Hz, so it wouldn't work.
Nanophoton…
4
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4 answers
What's the difference between Raman scattering and second harmonic generation in crystal?
As far as I know, the Raman scattering is from the stokes and anti-stokes scattering that the laser light interact with molecular vibrations. So we know that ""laser light interact with molecular vibrations"" in crystal can cause Raman…
sunnie
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2 answers
Phonon scattering process in raman spectroscopy
I am trying to understand diagrams that involve showing phonon scattering processes that contribute to raman spectroscopy peaks.
For example, I drew the one at the bottom of this post. This is supposed to the scattering process responsible for the D…
Abstracted
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Bosonic excitation investigated by scattering experiments in condensed matter physics
Why experimental tools like Raman scattering, Inelastic neutron scattering (INS), Resonant inelastic X-ray scattering (RIXS), etc., can only detect bosonic excitation?
Why electronic excitation won't involve in these processes?
Its common feature is…
PP21
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Raman Spectroscopy and Phonon Modes
How can someone use Raman Spectroscopy to obtain information for the phonon modes of a crystal? I am asking for some paper that contains information about Raman Spectroscopy and Phonons from an experimental point of view.
VladimirA
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How to determine if a calculated Raman mode in a crystal is active or not?
I have used an ab initio electronic structure code to calculate the harmonic Raman spectrum of a (molecular) crystal. However, no use of symmetry has been made, and it might well be that some of the vibrational modes that I obtained are actually…
Leinahtan
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3
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1 answer
Why does Raman activity depend on polarizability?
Raman spectroscopy essentially records photoluminescence:
(source)
and a molecule is considered to be Raman active when there is a change of polarizability $\alpha$ (where $\mathbf{P}=\alpha \mathbf{E}$) during vibration, $\left(\frac{\partial…
Sparkler
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