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Questions tagged [raman]

For questions relating to Raman scattering/effect and its applications as spectroscopy technique.

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Raman Spectrum of Graphene

I recently took a raman spectrum for a sample of graphene-pla. The result had the characteristic G and D bands associated with Graphene, but not the 2D. But there is a broad peak at around 3100, which ...
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How to distinguish two molecules with same formula but different geometry with vibrational spectroscopy

There is a sample that we know is all made up by only one of these two molecule: how you can see they have the same formula but two different geometries. The question is if it is possible to know by ...
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101 views

Raman spectra in Gaussian [closed]

I want to simulate Raman spectra of benzene in Gaussian 09. Calculated spectra for a single ring Benzene ($\ce{C6H6}$) in Gaussian differs about $\pu{40 cm^{-1}}$ for each peak, compared with ...
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structure information form IR and Raman spectra? [closed]

Is it possible to gain the idea of full molecular structure from IR or Raman spectroscopy?
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70 views

Absence of anti-Stokes line in Raman spectrum

If we have a molecule 1H-25X which shows a band at $3000~\mathrm{cm}^{-1}$ in the IR spectrum and you want to record a Stokes and anti-Stokes Raman spectrum with a laser of 1000 nm, why is the anti-...
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What is the difference of polarizability and dipole moment? [duplicate]

One is for Raman and the other is for IR. The words both have 'pole', so I often confused each other.
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How on the quantum level do the notch filters used in Raman spectroscopy remove only a select wavelength of light?

From what I have gathered regarding the schematics of Raman spectrometers, the notch filter is used to remove a narrow range of light corresponding to that of the laser used to excite the sample. How ...
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Raman database of polymer spectra for analyses in R/python

Can anyone reccomend a raman database of polymer spectra that is open source or freely available? I'm analyzing spectra of a number of plastics and looking for reference spectra for identification. ...
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Scan type of DFT calculations adding Freq=Raman keyword [duplicate]

I´m doing a scan calculation by adding Freq=Raman keyword. My objective is to obtain the Raman spectrum of each conformation in my compound. However, when i write the Freq=Raman Keyword, only the ...
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2answers
175 views

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

I am doing a scan calculation using Gaussian09 and adding the Freq=Raman keyword to my input file. My objective is to obtain the ...
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1answer
83 views

Raman activity in sulfur

I was wondering why sulfur is Raman active but other elements (e.g. carbon) are not.
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610 views

What drives the cost of Raman spectroscopy? [closed]

Raman spectroscopy setups are quite expensive- \$10-\$30k seems pretty common. The spectrometer, the probe/fiber cable, and the laser are typically each $3k+. The spectrometer could potentially be ...
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149 views

Spectroscopy pyrazine molecule

Considering pyridazine and pyrazine molecules, I am asked to say if I can distinguish one from the other in a sample. I supposed that is possible because pyrazine belongs to D2h and so it has the ...
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668 views

Identification of Sir Raman's handheld scope

I read an article somewhere around 5-10 years ago that talked a little bit about the life of Sir C. V. Raman. The focus was on the effect of Raman spectroscopy but included an interesting little ...
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501 views

Raman Spectroscopy: How to calculate their constants?

$^1{\ce{H2}}$ is interrogated with a laser of wavelength lambda = 532 nm and vibrational Stokes transitions are observed at S(0) = 14302.206 cm$^{-1}$, Q(0) = 14638.442 and O(2) = 14992.823 cm$^{-1}$. ...
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679 views

How to tell if a vibrational mode in benzene is IR and/or Raman active?

Consider the vibrational mode that corresponds to the boat-like bending of a benzene ring. Is it (i) Infrared active? (ii) Raman active? This question was asked in an assignment in my college. ...
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294 views

Raman Spectrum of carbon chains: How to identify the vibrational modes

So I am using NWChem to calculate the raman spectra of C2H2 and C4H4. For example for the first I obtained the following frequencies: ...
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1answer
629 views

Compound formed from concentrated sulfuric acid and sulfur

In the reaction below, I know what A and B are, but I'm not sure what compound C is. All I know about it is the following: Deep yellow solid Dication contains only sulfur Raman and infra-red spectra ...
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1answer
681 views

Why hydrofluoric acid (HF) has two Raman bands?

Hydrofluoric acid ($\ce{HF}$) is a diatomic molecule with only one vibrational coordinate. Therefore I would expect only one Raman band, however there are two. Why? (source)
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2answers
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Raman Spectra of Toluene

This is the raman spectra of Toluene I obtained while working at my lab using a raman spectrometer with laser of 532 nm wavelength. Well, I am a physics student, but I want to know how information ...
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SERS Gold nanoparticles performing poorly in organic solvents?

We have been working with some organic solvents lately and noticed a sharp decrease in surface-enhanced Raman spectroscopy (SERS) performance from our gold nanoparticles deposited in an organic ...
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1answer
858 views

Calculating Raman Intensities from Static Raman Activities

Whenever I want to calculate a Raman spectrum, my quantum chemical programs give me Raman scattering activities. As the common Raman spectrum is dependent on the incident wavelength of the used laser ...
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99 views

What are the strategies to deal with fluorescence from oil in Raman Spectroscopy?

I have a sample (for the purpose of this question let's call this Sample A) consisting of oil (edible olive oil) mixed with a contaminant (Contaminant B) from the Polycyclic Aromatic Hydrocarbons ...
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2answers
355 views

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

I'm just wondering why stoke-Raman doesn't go to the ground state. Where does the rest of energy from exciting laser leave? On the other hand, why does anti-stoke go back to ground state? I know that ...
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1answer
589 views

Role of Acetonitrile and Ammonium Acetate buffer in Leucomalachite Green stock solution?

I am trying to repeat an experiment conducted by FDA on Malachite Green (MG). According to this paper, ...
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2answers
3k views

Which are the differences between resonance Raman and fluorescence?

If the fluorescence is the re-emitting of a photon with a larger wavelenght due to the transition from a higher energy state to a lower energy state the case of resonance Raman (where there aren't any ...