Can resonance be used to split a molecule of CO2?

In summary, there are several factors that determine the frequency output of a laser diode, including the device design and choice of material. Therefore, it is not possible to calculate the frequency using only the information of the type of semiconductors used. It is best to either measure the frequency or read the specifications of the device.
  • #1
Sveral
63
1
Hello,
interested, if the posibility of splitting atoms by using resonance is possible, if so, wheather or not I can use it for something else, thanks in advance.
 
Physics news on Phys.org
  • #2
You mean to dissociate a molecule?

If so, what resonance are you thinking about?
 
  • #3
DrClaude said:
You mean to dissociate a molecule?

If so, what resonance are you thinking about?
Yes, exactly. I`m thinking about the dissociation of the nucleus of, for example, CO2 into Carbon and oxygen. Hope it makes sense
 
  • #4
You haven't said what resonance you are thinking about.
 
  • #5
DrClaude said:
You haven't said what resonance you are thinking about.
You mean, how I intend to create the resonance itself? Sound, very high frequency.
 
  • #6
You can't use sound to break a molecule like CO2.
 
  • #7
DrClaude said:
You can't use sound to break a molecule like CO2.
If the input frequency matches the frequency of self-oscillation of the bond between C and O, then, why not? Any ideas as to, where to find the frequencies of bonds between certain elements or how to calculate them?
 
  • #9
Sveral said:
If the input frequency matches the frequency of self-oscillation of the bond between C and O, then, why not? Any ideas as to, where to find the frequencies of bonds between certain elements or how to calculate them?
Even if you could do that in theory, molecular vibrations are highly non-linear, so there isn't a single frequency you could excite at. And the link you gave talks about using laser light, which is not the same thing! Even then, simply vibrationally exciting a molecule at a single frequency won't work, but time-varying frequencies are needed.

At the molecular level, a sound wave simply corresponds to collisions between molecules. Regular chemistry applies.
 
  • #10
Sveral said:
If the input frequency matches the frequency of self-oscillation of the bond between C and O, then, why not? Any ideas as to, where to find the frequencies of bonds between certain elements or how to calculate them?

There are several reasons. One is that frequencies involved in molecules are optical, i.e. a few THz at the very least. "Sound" in the usual sense of the word only goes up to a few MHz at most (for ultrasound). Note also that this neglects the (not so small) problem of how you would "convert" your (theoretical) sound into the energy needed to actually break the bond.
Also, just think of the wavelength of sound compared to the size of the molecule.

Note that both of the explanations above neglects a LOT of physics; I am merely trying to illustrate why it wouldn't work,
 
  • Like
Likes DrClaude
  • #11
f95toli said:
Also, just think of the wavelength of sound compared to the size of the molecule.
That is a point even one with my...knowledge can understand, well put.
f95toli said:
There are several reasons. One is that frequencies involved in molecules are optical, i.e. a few THz at the very least. "Sound" in the usual sense of the word only goes up to a few MHz at most (for ultrasound).
Ok, but what about the link I posted? It should mean, that it is doable with light...
 
  • #12
DrClaude said:
Even then, simply vibrationally exciting a molecule at a single frequency won't work, but time-varying frequencies are needed.
Much appreciated for the information. Thank you.
 
  • #14
DrClaude said:
It is done all the time with light. People have been working for decades now on breaking specific bonds in molecules.
Ok, but any ideas as to how to calculate the resonant frequency of a bond of C-O? Also are there any DIY verions of wideband light generation chips or something?
 
  • #15
Sveral said:
Ok, but any ideas as to how to calculate the resonant frequency of a bond of C-O?

The easiest is to look at the infrared spectrum http://webbook.nist.gov/cgi/cbook.cgi?ID=C124389&Type=IR-SPEC&Index=1

Sveral said:
Also are there any DIY verions of wideband light generation chips or something?
I don't think that the equipment needed to do this is within reach of a layman.
 
  • Like
Likes Sveral
  • #17
Any ideas as to, how one can calculate the output frequency of a laser diode by knowing the type of semiconductors used?
 
  • #18
Sveral said:
Any ideas as to, how one can calculate the output frequency of a laser diode by knowing the type of semiconductors used?
easier to measure it by observing the color of the laser light. Or more quantitatively, measuring the distance between fringes in an interference pattern
 
  • #19
Ben Wilson said:
easier to measure it by observing the color of the laser light. Or more quantitatively, measuring the distance between fringes in an interference pattern
Solid answer, but seems like I need to specify the question. If I know everything about every component that`ll be used for the building of the laser, how can I calculate the frequency using those numbers?
 
  • #20
Sveral said:
Solid answer, but seems like I need to specify the question. If I know everything about every component that`ll be used for the building of the laser, how can I calculate the frequency using those numbers?
Buy a laser where they tell you the frequency on the box. I think the calculations you want to do are very complex. But there may be simpler method that I've missed.
 
Last edited:
  • #21
Sveral said:
Any ideas as to, how one can calculate the output frequency of a laser diode by knowing the type of semiconductors used?

You can't. The laser frequency will depend on the details of the device design and the choice of material is only one of several factors. Laser diodes are complex devices built up of many semiconductor layers with different composition; there are also many different ways to make a laser diode (a InGaAs based VCSEL is very different from the "classical" red Si based diode).
Hence, you need to either measure it or just read the datasheet.
 
  • #22
f95toli said:
You can't. The laser frequency will depend on the details of the device design and the choice of material is only one of several factors. Laser diodes are complex devices built up of many semiconductor layers with different composition; there are also many different ways to make a laser diode (a InGaAs based VCSEL is very different from the "classical" red Si based diode).
Hence, you need to either measure it or just read the datasheet.
A. K. A. It's far from simple or DIY...
 
  • #23
You might enjoy looking up the HCl canon. It's a physical chemistry experiment with H2 and Cl2 in a container; it demonstres how a certain wavelength is needed to break a bond of diatomic chloride, forming HCl and a 'canon' effect.

E=h (nu) where nu is frequency and nu or sometimes f=v/lambda where v here would be the speed of light. Play with these and the energy of a CO2 bond (typically in kJ/mol - there's tables for it anywhere from google). That paired with the typical wavelength for sound help explain why that wouldn't really work. There are plenty of E/M wavelengths that will break the bond in question, though.
 
  • #24
Nino MMP said:
You might enjoy looking up the HCl canon. It's a physical chemistry experiment with H2 and Cl2 in a container; it demonstres how a certain wavelength is needed to break a bond of diatomic chloride, forming HCl and a 'canon' effect.
I would like to point out that in this case, the molecule dissociates due to electronic excitation, not vibrational excitation.
 
  • Like
Likes Nino MMP
  • #25
DrClaude said:
I would like to point out that in this case, the molecule dissociates due to electronic excitation, not vibrational excitation.

Oh okay, thank you for the correction DrClaude! Would atomic/optical books be best to read into this more? I am intrigued.
 
  • #26
Nino MMP said:
Oh okay, thank you for the correction DrClaude! Would atomic/optical books be best to read into this more? I am intrigued.
This will be covered in some books on atomic and molecular physics, but it is getting closer to chemistry than to physics.
 
  • Like
Likes Nino MMP
  • #27
DrClaude said:
This will be covered in some books on atomic and molecular physics, but it is getting closer to chemistry than to physics.

Ah okay great! Yep, unfortunately my passion seems to repeatedly be right at the interface of the physical sciences. Thank you, sir.
 
  • #28
Nino MMP said:
You might enjoy looking up the HCl canon. It's a physical chemistry experiment with H2 and Cl2 in a container; it demonstres how a certain wavelength is needed to break a bond of diatomic chloride, forming HCl and a 'canon' effect.

E=h (nu) where nu is frequency and nu or sometimes f=v/lambda where v here would be the speed of light. Play with these and the energy of a CO2 bond (typically in kJ/mol - there's tables for it anywhere from google). That paired with the typical wavelength for sound help explain why that wouldn't really work. There are plenty of E/M wavelengths that will break the bond in question, though.
Ok, will do, thanks.
 
  • Like
Likes Nino MMP
  • #29
May be too late to reply but as I recall to reach the first dissociation limit of CO2 to become CO and O, you need around 7.5 eV photon energy. You will need laser in the UV range to do this dissociation.
 
  • Like
Likes Nino MMP
  • #30
blue_leaf77 said:
May be too late to reply but as I recall to reach the first dissociation limit of CO2 to become CO and O, you need around 7.5 eV photon energy. You will need laser in the UV range to do this dissociation.
Actually useful, not too late.
 
  • #31
Nino MMP said:
Ah okay great! Yep, unfortunately my passion seems to repeatedly be right at the interface of the physical sciences. Thank you, sir.
I looked for the HCl cannon, but couldn`t seem to find it. Any chance you could toss in a link?
 
  • #32
Does anyone know of a good website , where one can nuclear magnetic resonance frequencies of aromatics and alkanes? (
toluene, m,p-xylene, 1,3,5-trimethylbenzene, benzene, and propene)
 
  • #34
  • #35
DrClaude said:
Even if you could do that in theory, molecular vibrations are highly non-linear, so there isn't a single frequency you could excite at. And the link you gave talks about using laser light, which is not the same thing! Even then, simply vibrationally exciting a molecule at a single frequency won't work, but time-varying frequencies are needed.

At the molecular level, a sound wave simply corresponds to collisions between molecules. Regular chemistry applies.
Could you us the Kuramoto model to synchronise the atoms first before applying a dissonant frequency?
 

Similar threads

Replies
10
Views
1K
  • Atomic and Condensed Matter
Replies
1
Views
1K
  • Atomic and Condensed Matter
Replies
18
Views
1K
  • Atomic and Condensed Matter
Replies
4
Views
1K
  • Atomic and Condensed Matter
Replies
4
Views
1K
  • Atomic and Condensed Matter
Replies
19
Views
1K
  • Atomic and Condensed Matter
Replies
3
Views
1K
  • Atomic and Condensed Matter
Replies
5
Views
2K
  • Atomic and Condensed Matter
Replies
2
Views
1K
  • Atomic and Condensed Matter
Replies
9
Views
4K
Back
Top