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9 votes
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Identification of Sir Raman's handheld scope

I think you are referring to a handheld prism based spectroscope with an eye-view/eyepiece. Using such spectroscope one does not observe Raman signal but only observe the dispersed light coming from ...
ankit7540's user avatar
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9 votes

Identification of Sir Raman's handheld scope

Sir Martyn Poliakoff did the video about the spectroscope on his Periodic Videos channel on youtube. To my knowledge, he presented the original instrument but did not mention where to obtain a ...
Klaus-Dieter Warzecha's user avatar
7 votes

How to obtain the Raman spectrum along every coordinate of a scan in Gaussian?

No, there is no automation for this, and there should not be. Using compound jobs is unfortunately very common among computational chemists, but they should always be viewed critically. If you are ...
Martin - マーチン's user avatar
6 votes
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Raman Spectrum of carbon chains: How to identify the vibrational modes

When you perform a IR or Raman calculation, the primary step is the diagonalization of the mass-weighted Hessian: $$ \begin{align} H_{ij,ab}^{\mathrm{mw}} &= \frac{1}{\sqrt{m_{i}m_{j}}} \frac{\...
pentavalentcarbon's user avatar
4 votes
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Are A1g modes reduced at 180 degrees polarisation in Raman spectra?

In solution the theoretical ratio of parallel to perpendicular polarised Raman intensity (measured relative to laser polarisation) is $\rho=3/4 $ if the mode is non-totally symmetric, and $0\lt \rho&...
porphyrin's user avatar
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4 votes
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Can you measure an IR spectrum of a sample inside a glass vial?

As EdV said, when you have aqueous samples, Raman spectroscopy is the way to go. The problem is not the container (which should not be glass etc),the problem is water. Its absorption will hide the ...
AChem's user avatar
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3 votes

Right Raman Spectrum of Cyclohexane

First of all, you are extremely lucky in asking this question for cyclohexane: cyclohexane serves as reference material for checking your intensity calibration, so it is one of the few substances for ...
cbeleites unhappy with SX's user avatar
3 votes
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Which are the differences between resonance Raman and fluorescence?

okay, old question, but: recall that the virtual state can always be decomposed as a sum over all real states, and the contribution of every real state to the superposition is determined by the ...
bill's user avatar
  • 46
3 votes

Raman Spectrum of Water

This answer is based on the educated guess that the green excitation Raman spectrum was acquired with a dispersive Raman instrument*. But why is there general nonzero background in intensity? What ...
cbeleites unhappy with SX's user avatar
3 votes

How to obtain the Raman spectrum along every coordinate of a scan in Gaussian?

Afaik it's not possible to do this directly since Gaussian does only allow geometry optimization during scans. The definitely easiest way to do this, but not the cheapest, would be running your scan, ...
DSVA's user avatar
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3 votes
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Compound formed from concentrated sulfuric acid and sulfur

The reaction is given here. $$\ce{S + 2H2SO4 → 3SO2 + 2H2O}$$ Sulfur react with sulfuric acid to produce sulfur dioxide and water. Sulfuric acid should be concentrated solution. The reaction takes ...
Nilay Ghosh's user avatar
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2 votes

Raman Spectra of Toluene

You have asked question about vibrational modes and functional groups with respect to Raman spectra. General information: Specific vibrational modes are deduced by normal-coordinate analysis. This ...
ankit7540's user avatar
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2 votes

Raman activity in sulfur

In a review (PDF, CalTech) of the properties of elemental sulfur, the author notes that the most stable form of sulfur at STP is in fact cycloocta-sulfur, $\ce{S8}$, with other polyatomic species also ...
AndyW's user avatar
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2 votes

How to distinguish two molecules with same formula but different geometry with vibrational spectroscopy

The starting point is to look at the potential point groups of the two molecules and work out if there are common vibrational mode symmetries between IR and Raman spectra, assuming that you are able ...
porphyrin's user avatar
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2 votes

Raman spectra in Gaussian

Thank you for attaching your input file. The first place to start for improving these calculations is your choice of basis set. 6-31G is a rather small basis set and is likely a source of significant ...
PJ R's user avatar
  • 1,394
2 votes

Raman Spectrum of Water

A background on Raman: Samzun (OP), buried in your query might be the taught belief that a Raman scatter spectrum is independent of the excitation wavelength, and this is mostly true, except for a ...
onix's user avatar
  • 23
2 votes
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Converting Raman Spectra to Infrared Spectra

Not in any way that you can use in practice for getting a working predictive model (= data analysis procedure). Depending on the molecular symmetry of your analyte(s), infrared and Raman spectra may ...
cbeleites unhappy with SX's user avatar
1 vote
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Is there a difference between $A_{1g}$ modes and $A_{g}$ modes?

To answer your question of A$_{1g}$ and A$_g$ are the same? No, they are not, because they correspond to irreducible representations of different symmetry point groups that differ in the allowed ...
Hemanth Haridas's user avatar
1 vote
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Raman scattering and "electron and proton center" of molecule

I guess for homogeneous read homo-nuclear. He is trying to explain how the electric field of the radiation induces a dipole by shoving the electrons around, hence reference to polarisability: this ...
porphyrin's user avatar
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1 vote

CNT Raman ratio of G band to 2D band?

I think there might be a mistake in your question... Around $\pu{2680 cm-1}$, there is the $S_1$ band (attributed to overtone or combination scattering). I think the $2D$ band you are referring to is ...
Okano's user avatar
  • 413
1 vote

Could coating silver inside of a cuvette be used for SERS?

from theory this should work what you have scatched here. When it comes to SERS a main point is, that you got a surface which is rough enough that you can create mini hot-spots for the electric field. ...
Andrea's user avatar
  • 261
1 vote

Raman Spectroscopy: How to calculate their constants?

In Raman spectroscopy the difference in frequency between the exciting line and the measured signal frequencies contains the information you want. These values, made positive if necessary, give the ro-...
porphyrin's user avatar
  • 30.6k
1 vote

Spectroscopy pyrazine molecule

You need to understand some details of using point group tables. The pyrazine belongs to $\ce{D_{2h}}$ point group and pyridazine belongs to $\ce{C_{2v}}$ In the third column of the point group are ...
porphyrin's user avatar
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1 vote

Calculating Raman Intensities from Static Raman Activities

You have two options in that case. You can try to understand the frequency dependent (or dynamic) property in the formulation for Raman activity. This property is a bit complex and is known as ...
ankit7540's user avatar
  • 1,582
1 vote

Why does Stokes raman not relax to the ground state while anti-Stokes does?

It is really a matter of definition. Rayleigh scattering does not involve any change to the internal energy of the molecule whereas Raman transitions do. The Raman transitions always involve a change ...
porphyrin's user avatar
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