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Can somebody explain what a "virtual energy state" is? How is this distinct from a "true" energy transition (presumably one where the electrons are moved to an excited state)?
Okay, so here's an analogy: You throw a tennis ball at a wall with a strange spring device in it (the details aren't important, but imagine the spring can be either compressed or relaxed, and it's got a way of being held in compression which can be toggled by the tennis ball). The tennis ball bounces back. If it comes back faster than it went in, then you know the spring was compressed, and got released by the tennis ball. By looking at the change in the ball's speed you can tell how much energy was in the spring. If it comes back slower than it went in, then you know the spring was relaxed and became compressed by the tennis ball. That's all that's going on, except that the photon's energy is given by its frequency rather than its speed. Also it's probably not the same tennis ball, but an identical one because of quantum mechanical stuff. So in the analogy, the spring needs to absorb a tennis ball with a very particular speed to become compressed - a speed much less than the speed of the tennis ball. But somehow it manages to absorb the tennis ball anyway, and it copes with all the extra speed by immediately releasing another tennis ball going slightly slower than the one that came in. Grj23 ( talk) 11:21, 4 December 2008 (UTC)
Can someone provide more information on the following statement: "the lateral and depth resolutions were 250 nm and 1.7 µm, respectively, using a confocal Raman microspectrometer with the 632.8 nm line from a He-Ne laser with a pinhole of 100 µm diameter." The microscopic magnification would be an important piece of information if these resolution numbers are to be reproduced.
Mill haru 02:24, 8 January 2007 (UTC)
What does it mean that "The fingerprint region of organic molecules is in the range 500-2000 /cm"? If wavelengths are in units of length then why is the "fingerprint" given in inverse length?
This article could use some reorganizing: history should come before applications and applications should be merged with Raman microspectroscopy, other types, and see also. Additionally, at least in the RR article, there is a significant amount of repeated information, which may be more appropriately placed the main Raman article. Finally, the theory section should be expanded or an advance theory section should be added to do this topic justice.-- Bjsamelsonjones
I think an experimental set-up section would also be a good idea. Including monochromatic incident light, reflection of the sample, filter to remove the rayleigh scattered light of the same frequency as the incoming light (which constitutes the bulk of the reflected light) a disperser (I think), and a detector. What disperser is used nowadays? Do practitioners use a michelson interferometer and fourier transform like in infrared spectroscopy? 131.111.74.86 ( talk) 16:36, 5 June 2008 (UTC)
This is a strange sentence: "Consequently in vivo time- and space-resolved Raman spectroscopy is suitable to measure cells, proteins, organs, and erythrocytes." First of all, what is meant by "measuring" cells or organs? Measuring the quantity or characterizing their chemical composition? Secondly, erythrocytes are a type of cell, so to say that Raman spectroscopy is suitable for measuring cells AND erythrocytes is redundant. —Preceding unsigned comment added by 69.181.124.113 ( talk • contribs)
Hi every one, I would say that I am not completely agree with the example proposed to describe the lateral and depth resolution for a Raman microspectrometer.
First, about the lateral resolution of 250 nm. I think that a lateral resolution of 250 nm could be reached but not with a confocal microscope only. For your example, with a conventional Raman microspectrometer equipped with a He-Ne (632,81 nm) and a dry microscope objective of x100 (Numerical aperture = 0.9), the best lateral resolution you could have is around 1 micrometer. I think a resolution of 250 nm can be reached on AFM instrument coupled with a Raman spectrometer.
Secondly, the depth resolution depend on the nature on the sample. On a Si Wafer, the depth resolution is closed to 1 µm. On bone, the depth resolution decrease to 5 µm. It depends on the homogeneity of the sample. Generally, in spectroscopist review, everybody agree that the depth resolution is close to 1 µm.
If you want, I have reference concerning the use of Polarized Raman experiments in order to determine apatite crystals orientation in human teeth.
Capsulcorp (
talk) 15:16, 27 June 2008 (UTC)
Hi, I have to add something too. Is the graphic showing the raman energy levels correct that way? Atkins (Physical Chemistry) shows ∆J=±2. And the graphic in that book shows a difference in J before and after (anti-)stokes of (-)2. —Preceding
unsigned comment added by
91.60.65.108 (
talk) 02:41, 9 December 2008 (UTC)
The image File:CVRaman.jpg is used in this article under a claim of fair use, but it does not have an adequate explanation for why it meets the requirements for such images when used here. In particular, for each page the image is used on, it must have an explanation linking to that page which explains why it needs to be used on that page. Please check
This is an automated notice by FairuseBot. For assistance on the image use policy, see Wikipedia:Media copyright questions. --09:46, 3 January 2009 (UTC)
A citation for use of Raman spectroscopy with a wide range of excitation wavelengths is currently Reference [14], but this citation seems to be actually about biomedical imaging. This citation numbering issue should be investigated/resolved. — Preceding unsigned comment added by Slepkov ( talk • contribs) 16:43, 14 October 2011 (UTC)
The doi of the Lombardi paper is wrong, it should be 10.1021/jp800167v. I don't know how to fix this and I don't have the time to read the manual.
It would be nice if the article included more info on isotope analysis with Raman microspectroscopy. This is a technique that is used in ecology and probably elsewhere. -- 151.205.213.57 ( talk) 04:22, 9 May 2009 (UTC)
I'm wondering if Brillouin scattering should be included with Rayleigh in the context of scattering close to the exciter line. Periksson28 ( talk) 19:46, 18 July 2009 (UTC)
I believe the description of spatially offset Raman spectroscopy, under variations, has been cut off. — Preceding unsigned comment added by 134.169.63.23 ( talk) 10:05, 15 June 2012 (UTC)
Isn't there a slight mistake in that image? As far I know the selection rule for IR-spectroscopy is v = ± 1 (not 2)!
Regarding the several comments about the energy level diagram at the top, the infrared absorption transition should match the Raman transition to make the essential point that the energy difference between the excitation photon and the Raman scattered photon is equal to the energy of the infrared transition. v = 0 to v = 1 is a good choice because it is very typical. The file Raman energy levels.jpg should be edited or replaced, so that the short blue arrow on the left (Infrared absorption) extends from 0 to 1, rather than from 0 to 2.
(For example, see Fig. 1.8 of “Introduction to Raman Spectroscopy, 2nd Edition”, Ferraro, Nakamoto and Brown, Academic Press, 2003.)
02:51, 15 April 2016 (UTC) — Preceding unsigned comment added by Propanscience ( talk • contribs)
I'm just reading the article and encountered the term "rovibronic", which is explained after used. That term isn't in Dictionary.com and a lot of other word dictionaries. It might be a bit obscure for casual readers - it's complete jargon. While technically correct and the correct term, consider rewording the passage using different terms to be better understood by a less-technical reader. — Preceding unsigned comment added by 71.241.129.12 ( talk) 23:16, 13 December 2016 (UTC)
This article is kind of a mess and I'd like to improve it but I'm not sure how to proceed. There is clearly a lot of overlap with the Raman scattering page. It would make sense to me if the Scattering page focused more on theory and this page focused more on the practical aspects (but in some instances this page has better discussion of theory). The section on polarization for instance is better in this page. The Scattering page doesn't discuss depolarization ratios at all which someone should fix.
Another thing is the microscopy (microspectrometry) section which I see @ Toommm: has been doing some nice work on lately. If that section gets too big I would suggest spinning off a second article. Perhaps the Variants section could also be separated.
I would suggest adding a section discussing instrumentation (detectors, spectrographs, filters and so on).
I am also planning to add a section about low-frequency Raman some day as well.
Thoughts? Pelirojopajaro ( talk) 12:25, 3 July 2019 (UTC)
This is the
talk page for discussing improvements to the
Raman spectroscopy article. This is not a forum for general discussion of the article's subject. |
Article policies
|
Find sources: Google ( books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL |
This
level-5 vital article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||||||||||||
|
This article links to one or more target anchors that no longer exist.
Please help fix the broken anchors. You can remove this template after fixing the problems. |
Reporting errors |
Can somebody explain what a "virtual energy state" is? How is this distinct from a "true" energy transition (presumably one where the electrons are moved to an excited state)?
Okay, so here's an analogy: You throw a tennis ball at a wall with a strange spring device in it (the details aren't important, but imagine the spring can be either compressed or relaxed, and it's got a way of being held in compression which can be toggled by the tennis ball). The tennis ball bounces back. If it comes back faster than it went in, then you know the spring was compressed, and got released by the tennis ball. By looking at the change in the ball's speed you can tell how much energy was in the spring. If it comes back slower than it went in, then you know the spring was relaxed and became compressed by the tennis ball. That's all that's going on, except that the photon's energy is given by its frequency rather than its speed. Also it's probably not the same tennis ball, but an identical one because of quantum mechanical stuff. So in the analogy, the spring needs to absorb a tennis ball with a very particular speed to become compressed - a speed much less than the speed of the tennis ball. But somehow it manages to absorb the tennis ball anyway, and it copes with all the extra speed by immediately releasing another tennis ball going slightly slower than the one that came in. Grj23 ( talk) 11:21, 4 December 2008 (UTC)
Can someone provide more information on the following statement: "the lateral and depth resolutions were 250 nm and 1.7 µm, respectively, using a confocal Raman microspectrometer with the 632.8 nm line from a He-Ne laser with a pinhole of 100 µm diameter." The microscopic magnification would be an important piece of information if these resolution numbers are to be reproduced.
Mill haru 02:24, 8 January 2007 (UTC)
What does it mean that "The fingerprint region of organic molecules is in the range 500-2000 /cm"? If wavelengths are in units of length then why is the "fingerprint" given in inverse length?
This article could use some reorganizing: history should come before applications and applications should be merged with Raman microspectroscopy, other types, and see also. Additionally, at least in the RR article, there is a significant amount of repeated information, which may be more appropriately placed the main Raman article. Finally, the theory section should be expanded or an advance theory section should be added to do this topic justice.-- Bjsamelsonjones
I think an experimental set-up section would also be a good idea. Including monochromatic incident light, reflection of the sample, filter to remove the rayleigh scattered light of the same frequency as the incoming light (which constitutes the bulk of the reflected light) a disperser (I think), and a detector. What disperser is used nowadays? Do practitioners use a michelson interferometer and fourier transform like in infrared spectroscopy? 131.111.74.86 ( talk) 16:36, 5 June 2008 (UTC)
This is a strange sentence: "Consequently in vivo time- and space-resolved Raman spectroscopy is suitable to measure cells, proteins, organs, and erythrocytes." First of all, what is meant by "measuring" cells or organs? Measuring the quantity or characterizing their chemical composition? Secondly, erythrocytes are a type of cell, so to say that Raman spectroscopy is suitable for measuring cells AND erythrocytes is redundant. —Preceding unsigned comment added by 69.181.124.113 ( talk • contribs)
Hi every one, I would say that I am not completely agree with the example proposed to describe the lateral and depth resolution for a Raman microspectrometer.
First, about the lateral resolution of 250 nm. I think that a lateral resolution of 250 nm could be reached but not with a confocal microscope only. For your example, with a conventional Raman microspectrometer equipped with a He-Ne (632,81 nm) and a dry microscope objective of x100 (Numerical aperture = 0.9), the best lateral resolution you could have is around 1 micrometer. I think a resolution of 250 nm can be reached on AFM instrument coupled with a Raman spectrometer.
Secondly, the depth resolution depend on the nature on the sample. On a Si Wafer, the depth resolution is closed to 1 µm. On bone, the depth resolution decrease to 5 µm. It depends on the homogeneity of the sample. Generally, in spectroscopist review, everybody agree that the depth resolution is close to 1 µm.
If you want, I have reference concerning the use of Polarized Raman experiments in order to determine apatite crystals orientation in human teeth.
Capsulcorp (
talk) 15:16, 27 June 2008 (UTC)
Hi, I have to add something too. Is the graphic showing the raman energy levels correct that way? Atkins (Physical Chemistry) shows ∆J=±2. And the graphic in that book shows a difference in J before and after (anti-)stokes of (-)2. —Preceding
unsigned comment added by
91.60.65.108 (
talk) 02:41, 9 December 2008 (UTC)
The image File:CVRaman.jpg is used in this article under a claim of fair use, but it does not have an adequate explanation for why it meets the requirements for such images when used here. In particular, for each page the image is used on, it must have an explanation linking to that page which explains why it needs to be used on that page. Please check
This is an automated notice by FairuseBot. For assistance on the image use policy, see Wikipedia:Media copyright questions. --09:46, 3 January 2009 (UTC)
A citation for use of Raman spectroscopy with a wide range of excitation wavelengths is currently Reference [14], but this citation seems to be actually about biomedical imaging. This citation numbering issue should be investigated/resolved. — Preceding unsigned comment added by Slepkov ( talk • contribs) 16:43, 14 October 2011 (UTC)
The doi of the Lombardi paper is wrong, it should be 10.1021/jp800167v. I don't know how to fix this and I don't have the time to read the manual.
It would be nice if the article included more info on isotope analysis with Raman microspectroscopy. This is a technique that is used in ecology and probably elsewhere. -- 151.205.213.57 ( talk) 04:22, 9 May 2009 (UTC)
I'm wondering if Brillouin scattering should be included with Rayleigh in the context of scattering close to the exciter line. Periksson28 ( talk) 19:46, 18 July 2009 (UTC)
I believe the description of spatially offset Raman spectroscopy, under variations, has been cut off. — Preceding unsigned comment added by 134.169.63.23 ( talk) 10:05, 15 June 2012 (UTC)
Isn't there a slight mistake in that image? As far I know the selection rule for IR-spectroscopy is v = ± 1 (not 2)!
Regarding the several comments about the energy level diagram at the top, the infrared absorption transition should match the Raman transition to make the essential point that the energy difference between the excitation photon and the Raman scattered photon is equal to the energy of the infrared transition. v = 0 to v = 1 is a good choice because it is very typical. The file Raman energy levels.jpg should be edited or replaced, so that the short blue arrow on the left (Infrared absorption) extends from 0 to 1, rather than from 0 to 2.
(For example, see Fig. 1.8 of “Introduction to Raman Spectroscopy, 2nd Edition”, Ferraro, Nakamoto and Brown, Academic Press, 2003.)
02:51, 15 April 2016 (UTC) — Preceding unsigned comment added by Propanscience ( talk • contribs)
I'm just reading the article and encountered the term "rovibronic", which is explained after used. That term isn't in Dictionary.com and a lot of other word dictionaries. It might be a bit obscure for casual readers - it's complete jargon. While technically correct and the correct term, consider rewording the passage using different terms to be better understood by a less-technical reader. — Preceding unsigned comment added by 71.241.129.12 ( talk) 23:16, 13 December 2016 (UTC)
This article is kind of a mess and I'd like to improve it but I'm not sure how to proceed. There is clearly a lot of overlap with the Raman scattering page. It would make sense to me if the Scattering page focused more on theory and this page focused more on the practical aspects (but in some instances this page has better discussion of theory). The section on polarization for instance is better in this page. The Scattering page doesn't discuss depolarization ratios at all which someone should fix.
Another thing is the microscopy (microspectrometry) section which I see @ Toommm: has been doing some nice work on lately. If that section gets too big I would suggest spinning off a second article. Perhaps the Variants section could also be separated.
I would suggest adding a section discussing instrumentation (detectors, spectrographs, filters and so on).
I am also planning to add a section about low-frequency Raman some day as well.
Thoughts? Pelirojopajaro ( talk) 12:25, 3 July 2019 (UTC)