Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: lessdum_x on 11/01/2011 21:14:07

Title: Do molecules have unique frequencies of vibration?
Post by: lessdum_x on 11/01/2011 21:14:07
Does every molecule vibrate at a certain rate ? say proteins or whatever, will they have a unique vibration ? like all hemoglobin molecules have the same vibration while other proteins have a different one?

If there is an individuality of vibration , can this vibration signal be detected in some way?



Title: Re: Do molecules have unique frequencies of vibration?
Post by: Bored chemist on 11/01/2011 22:04:23
Sort of.
Have a look here
http://en.wikipedia.org/wiki/Infrared_spectroscopy
Having said that, there would be a lot of similarity between the spectra of different proteins. It would be difficult to tell them apart.
Title: Re: Do molecules have unique frequencies of vibration?
Post by: lessdum_x on 13/01/2011 00:27:06
Thanks for the link,

is it possible for say to "see" proteins as blobs of light ?  i mean take a sample and illuminating it with some kind of energy , and the proteins absorb it and then release it back , wouldn't we be able to detect that and see what goes on inside a cell?
Title: Re: Do molecules have unique frequencies of vibration?
Post by: yor_on on 13/01/2011 00:48:43
We do it when we inject/infuse people with different very weak solutions that have a certain wavelength inside the body. Then we bombard the body with EM-energy and those infusions start to reflect back showing us how the cellular level looks inside. Don't remember the name for it but we use it.
Title: Re: Do molecules have unique frequencies of vibration?
Post by: lessdum_x on 13/01/2011 01:11:11
would using a fluid substance be something that could interfere with natural movements of proteins and molecules of the cell and not give the full picture?

Imagine shining a lazer at a cell, and you could see all  different types of molecules as lights - with out no additional materials put inside , and perhaps a way to see how different kinds of proteins link up with what other kinds , so you can then build up a logic diagram for the cell, (sounds like science fiction but im sure we will have this in this capability soon.


just knowing how to give energy to a molecule and be able to receive the transmitted energy from it.

Title: Re: Do molecules have unique frequencies of vibration?
Post by: yor_on on 13/01/2011 01:30:04
You are thinking of matter waves here, they are incredibly short as I understands it and Impossible to detect for us. That's different from using, for example, something mildly radioactive that you then bombard to get up its 'energy/reflections' or just 'monitor'. I don't think we can measure matter waves.
==

Yeah, using a fluid could in theory introduce new effects, maybe? But the body already are made of different fluids :) Well, sort of, densities then. So I don't expect it to matter that much, but you have a point there.
Title: Re: Do molecules have unique frequencies of vibration?
Post by: lessdum_x on 14/01/2011 22:25:56

I was doing a little searching on the internet and saw a technique called "coherent anti stokes raman micrscopy" i havent a clue how it works but it seems very interesting, its picking up the vibrations from the molecules by using a laser,

do you think this method will be the future?

http://en.wikipedia.org/wiki/Coherent_anti-Stokes_Raman_spectroscopy
Title: Re: Do molecules have unique frequencies of vibration?
Post by: yor_on on 21/01/2011 17:31:25
Yep, been wondering why we don't use that kind of combinations for non-intrusive 'surgery'. I don't really know but it seems possible to 'cut' with it, as well as burn away?

It opens for a scary future though, where you can get lobotomized over your lunch break for having uncomfortable thoughts :)
Title: Re: Do molecules have unique frequencies of vibration?
Post by: Bored chemist on 21/01/2011 17:47:48
"just knowing how to give energy to a molecule and be able to receive the transmitted energy from it."
That's a lot easier than it sounds.
When I look at my hand I can see a scar on it. The light from the sun is absorbed by some bits of my hand more than by others so when I see the light reflected from it those bits look different. Reflection can be regarded as absorption followed by emission, so I give the molecules some energy and they give it back.
We could, using a microscope, look at individual protein molecules but there are two problems. First the proteins are so small that you cannot see them, even with a microscope.
The second is that they all look pretty much the same. Most proteins have very similar absorptions. In effect, they are all white so you are looking for something white on a white background.
The absorptions in the infra red are slightly different for different proteins, but the differences are very small. It would be like looking for something blue on a background that is a very similar shade of blue.
The trick people use is to get a dye that only sticks to one sort of protein. Then you can see it, because it's the only coloured thing on a white background.
Even then, you can't see individual molecules because they are too small.


Title: Re: Do molecules have unique frequencies of vibration?
Post by: yor_on on 21/01/2011 18:39:37
"CARS is a third-order nonlinear optical process involving three laser beams: a pump beam of frequency ωp, a Stokes beam of frequency ωS and a probe beam at frequency ωpr. These beams interact with the sample and generate a coherent optical signal at the anti-Stokes frequency (ωpr+ωp-ωS). The latter is resonantly enhanced when the frequency difference between the pump and the Stokes beams (ωp-ωS) coincides with the frequency of a Raman resonance, which is the basis of the technique's intrinsic vibrational contrast mechanism.[1][2]"

It was this I was thinking of BC, targeting cells actively. And that's also what I've been wondering about for some years. If it would be possible to use it for surgery?