EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: RoGeorge on August 20, 2023, 09:04:25 am
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The atoms and/or the molecules are kept together by electrons. In fact, most of the properties of any material are given by the electrons that keep the nuclei in certain arrangements or shapes, right?
If so, will the material suddenly atomize if all the electrons were to be pulled away? The remaining positively charged nuclei should repel each other.
So why materials doesn't disintegrate when positively charged? How many electrons can be removed before noticing different properties in the material? Why, for example, the electrostatic charging (by induction) doesn't disintegrate the positively charged side of a material?
Are these assumptions correct just that quantitatively their effects will be insignificant, or am I missing something?
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You would not be able to remove enough electrons before the force gets considerable. Plug in 1C x 2 and 1km into this calculator and you'll get 9000N force.
https://www.calctool.org/electromagnetism/coulombs-law (https://www.calctool.org/electromagnetism/coulombs-law)
The electrostatic force is very strong.
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EI (and other) ionization techniques are used in mass spectrometry to make the resulting positively charged ions break apart. I am relatively sure that's not what you mean, but the longest journey begins with the first step.
Just what sort of energies would be needed to completely ionize any bulk material?
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The atoms and/or the molecules are kept together by electrons. In fact, most of the properties of any material are given by the electrons that keep the nuclei in certain arrangements or shapes, right?
Yes correct.
If so, will the material suddenly atomize if all the electrons were to be pulled away? The remaining positively charged nuclei should repel each other.
If you were able to remove all the electrons, yes, but it's essentially impossible for any significant amount of bulk material. The forces required would be vast, and if you somehow managed it the material would be so charged as to rip electrons from surrounding matter.
So why materials doesn't disintegrate when positively charged? How many electrons can be removed before noticing different properties in the material? Why, for example, the electrostatic charging (by induction) doesn't disintegrate the positively charged side of a material?
Because you never remove very many of the electrons. Something that is electrostatically positively charged still has the vast majority of it's electrons. Consider if you take a 1 kg block of copper, it contains something like 1e25 atoms of copper and 3e26 electrons. Form that copper into a sphere and it's around 6 cm in diameter, with a capacitance to free space of 3 pF. Let's say you charge that sphere to 10 million volts, you have then removed Q=V*C = 3e-5 Coulombs of charge which we divide by the charge per electron (1.6e-19 C) to show is about 2e14 electrons. Out of 3e26 electrons you have only removed 2e14 of them which is less than one in 10,000,000,000,000,000,000,000.
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Didn't follow the calculation completely but the last division gives 1.5e12. For all practical purposes it's similar to the 1e22 you wrote down..
Regards, Dieter
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Indeed the net charge imbalance is miniscule. The Feynman Lectures on Physics (Vol. II, Ch. 1, https://www.feynmanlectures.caltech.edu/II_01.html#Ch1-S1 (https://www.feynmanlectures.caltech.edu/II_01.html#Ch1-S1)) explain this in a rather graphical way:
If there were even a little bit of unbalance you would know it. If you were standing at arm’s length from someone and each of you had one percent more electrons than protons, the repelling force would be incredible. How great? Enough to lift the Empire State Building? No! To lift Mount Everest? No! The repulsion would be enough to lift a “weight” equal to that of the entire earth!
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EI (and other) ionization techniques are used in mass spectrometry to make the resulting positively charged ions break apart. I am relatively sure that's not what you mean, but the longest journey begins with the first step.
Just what sort of energies would be needed to completely ionize any bulk material?
Was not sure what EI stands for and searched for "EI (and other) ionization techniques" and one of the results was this: https://en.wikipedia.org/wiki/Electrospray_ionization
Seems that at least one type of such disintegration I was asking about (by removing all the electrons) is already in use. :D
I didn't try any numerical estimations so far, it was just a funny "what if" question. I guess the needed energy is not inimaginably high. Should be about the same order of magnitude with the energy released (or handled) in various chemical reactions.
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EI (and other) ionization techniques are used in mass spectrometry to make the resulting positively charged ions break apart. I am relatively sure that's not what you mean, but the longest journey begins with the first step.
Just what sort of energies would be needed to completely ionize any bulk material?
Was not sure what EI stands for and searched for "EI (and other) ionization techniques" and one of the results was this: https://en.wikipedia.org/wiki/Electrospray_ionization
Seems that at least one type of such disintegration I was asking about (by removing all the electrons) is already in use. :D
I didn't try any numerical estimations so far, it was just a funny "what if" question. I guess the needed energy is not inimaginably high. Should be about the same order of magnitude with the energy released (or handled) in various chemical reactions.
In the case of a medium-size atom such as copper, only the outer electron shells, with relatively low binding energy, contribute to electrical conduction and the covalent bond that holds the crystal or amorphous state together.
The innermost K shell has a binding energy of roughly 9 keV, more than 1000x the first ionization energy of about 7.7 eV.
Getting all the electrons out is, shall we say, difficult.
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To fully ionize the average atom in an average object, takes somewhere between a few keV and low MeV per atom.
The corresponding energy put into the atom, gives it as much repulsion from others (mutual positive charge), or as much attraction to any electrons that can possibly be found nearby.
These are fusion level energies, of course you need not just density but dwell time (together: confinement) to pull that off in quantity.
The energy of a nuke corresponds to about 80MeV per fission event, of which there's a few kg of U or Pu in the core. A few dozen kg of regular matter, so prepared, therefore contains equivalent energy.
It's one of those problems where the concept is easy, but there's absolutely no meaningful route to preparing such a state from ground level, let alone with any kind of energy efficiency.
Tim
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What would you do with all those removed electrons ? ::) wher would you store them.
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I didn't try any numerical estimations so far, it was just a funny "what if" question. I guess the needed energy is not inimaginably high. Should be about the same order of magnitude with the energy released (or handled) in various chemical reactions.
Yes, the energy is truly, unimaginably high. It's not chemical reaction scale, it's nuclear reaction scale.
For any appreciable mass of material, the energy required to remove even a small fraction of the electrons would make it impossible to do. Even if somehow you did manage to remove a small fraction of electrons, the forces involved would rip surrounding matter apart. It just cannot be done.
When you positively charge an object, the number of electrons removed compared to the number of the electrons that remain is effectively zero. Even with highly charged objects, the ratio of negative charges to positive charges that remain continues to be 1:1 by any normal scale of measurement.
What can be done with individual atoms or molecules in an ionization chamber is different. Here, the scale is so small that even huge amounts of energy, relatively speaking, become accessible. It's a lot of energy per atom, but a small amount of energy in total.
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When you positively charge an object, the number of electrons removed compared to the number of the electrons that remain is effectively zero.
Are simple molecules "objects" in your analysis. Clearly in mass spectrometry, the fraction of electrons removed is not necessarily zero.* Now, for bulk materials, I agree.
*For small molecules like CO2,1 of 22 is 4.5%
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Ordinarily in mass spectrometry, the ionization removes only one or two electrons, since the rest are more tightly bound and one or two suffice.
I have done momentum spectrometry on H+ and H2+ ions, where the fraction removed is substantial.
For an electrophorus, only a small fraction of the electrons are removed.
A spokesman for electrons said he was glad that only a small fraction was involved.
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When you positively charge an object, the number of electrons removed compared to the number of the electrons that remain is effectively zero.
Are simple molecules "objects" in your analysis. Clearly in mass spectrometry, the fraction of electrons removed is not necessarily zero.* Now, for bulk materials, I agree.
Obviously, by object I mean an everyday object at macro scale, not a molecule. See the last paragraph of my post.
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I read something years ago that stated a mole of hydrogen and its stripped electrons placed on opposite sides of the earth would attract each other with enough force to pull their containers through the earth.
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To fully ionize the average atom in an average object, takes somewhere between a few keV and low MeV per atom.
The corresponding energy put into the atom, gives it as much repulsion from others (mutual positive charge), or as much attraction to any electrons that can possibly be found nearby.
These are fusion level energies, of course you need not just density but dwell time (together: confinement) to pull that off in quantity.
The energy of a nuke corresponds to about 80MeV per fission event, of which there's a few kg of U or Pu in the core. A few dozen kg of regular matter, so prepared, therefore contains equivalent energy.
It's much worse than that actually. Or better, depending on how much you like giant explosions. But we are talking a mass extinction level event.
It's not ionizing atoms or molecules in isolation that is the biggest effect, although it takes a lot of energy to ionize a mol of iron or whatnot. But the real energy is in the columb repulsion between all of the nucleii left over. which grows approximately quadratically, so it gets big *fast* for avogadro number of elementary charges.
The self assembly energy of a sphere of uniform charge is U = 3/5 * Q^2/(4*pi*eps_0 * r) (this ignores the lumpiness of the individual atoms and their individual ionization energy).
12 grams of carbon (1 mol), which is a bit under 1 cm radius sphere of graphite and has 6 mol of elecrtons. With the electrons removed would have an electric self energy of 10^23 joules. That's a _million_ times more powerful than the Tsar Bomba, and approximately the energy from the Chicxulub impact that lead to the extinction of the non-avian dinosaurs.
A 75 kg ball of carbon (like a human) would have and explode with millions of times more energy than that. More than enough energy to boil the ocean and melt the earth.
Somewhere around a ton of matter so de-electronified would have enough energy to literally vaporize the earth, exceeding it's own gravitational self energy and blasting it apart into interplanetary space.
Obviously you couldn't actually create any of this. If you start with a neutrally charged object and start pulling electrons out, it gets harder and harder to do so as the net charge gets more positive. If you somehow find a way to avoid that and keep going, the coulomb repulsion would exceed the inter-atomic binding energy and the object would just explode. Roughly speaking this would happen when the energy above were similar to conventional chemical reactions. If you somehow confined it against this tendency to explode, the resulting electric field would tear apart any matter nearby and pull away it's electrons to balance the charge. If you somehow held it together and kept all other matter away, eventually I guess it would start causing pair production, capturing the electrons and radiating the positrons.
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I think I once pondered the energy of, say, a softball of--- oh, no maybe it was a pound of electrons, something like that -- in isolation. Basically the same problem. I don't remember the scale of the setup anymore (and I can't look it up, it was on a long-defunct forum; although maybe it's archived somewhere, hm..), but something like that, pretty much.
You would indeed need one hell of a trap to contain such a beast; and I have no idea how you'd assemble it, you can't just boil off electrons (..maybe an ever-increasing spectrum of hard gamma rays??); maybe it would be easier to assemble protons (or electrons as the case may be) rather than stripping something.
Needless to say, utterly unimaginable magnet energy is required to construct such a trap; far more energy than contained in the trapped particles themselves. Electric field too (if it's a cross-field trap; I forget what kinds would be likely here).
The pair production limit is, https://en.wikipedia.org/wiki/Schwinger_effect
and presumably further particles at ever higher field strengths, but you're smashing some serious laser power by then (we haven't even begun to approach this limit yet, let alone further limits).
Tim
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I'm fairly sure the energy required to strip all the electrons off atoms in a material will already be more than enough to have heated the material enough for it to boil or sublimate. And I don't think there is any way energy could be supplied to a material to liberate electrons which wouldn't also result in heating of the material. Though once liberated it is likely you'd be able to say that the electrons and atoms would each have very different "temperatures".
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I suspect one day in the distant future maintaining electron free materials will be something of a interstellar effort akin to the LHC. God knows what kind of things can happen with such a material.
Would you be surprised if this was the kind of stuff you needed for processes that make say exotic matter?
can a black hole be used to power such a device?
The path of light is not affected by the presence of electric or magnetic field. However, in quantum electrodynamics, nonlinear terms appear in the effective action from the vacuum polarization effect. Then the path of light can be bent when the light passes around a strong electric or magnetic field.
Does the light bend equally with frequency? Can it be used to make a gamma ray separator (like a prism?)
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Some people have a googleplex too much time on their hands.
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Some people have a googleplex too much time on their hands.
And if you google it you'll find it's googolplex, Googlepex is Google's headquarters...
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A common error is confusing "googol" (common noun) with "Google" (proper noun).
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Google with goggle, too. :)
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In natural languages, spelling is often arbitrary, but it can help to resolve a gaggle of ambiguities.
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That made me giggle.
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Just what sort of energies would be needed to completely ionize any bulk material?
For Hydrogen we are talking 13.7eV (iirc) per Atom so about 1.3MJ/g or roughly 300 Times the energy density fo TNT.
And that is ignoring energy required to compress the protons to a sphere with a noninfinite radius.
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Spelling is my curse. Thanks for the correction.
Edit: I just spent a half hour going down a mathematical rabbit hole that made me realize I should have said a "Graham's number" instead of a "googolplex". Read about that, if you dare. And if your head has still not exploded, there are "busy beaver" numbers. We're gonna need a bigger universe.
Some people have a googleplex too much time on their hands.
And if you google it you'll find it's googolplex, Googlepex is Google's headquarters...
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Just what sort of energies would be needed to completely ionize any bulk material?
For Hydrogen we are talking 13.7eV (iirc) per Atom so about 1.3MJ/g or roughly 300 Times the energy density fo TNT.
And that is ignoring energy required to compress the protons to a sphere with a noninfinite radius.
The mnemonic I was taught: the ionization energy of the hydrogen atom is 13.6 eV, same as the density of liquid mercury in g/cm3.
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Just what sort of energies would be needed to completely ionize any bulk material?
For Hydrogen we are talking 13.7eV (iirc) per Atom so about 1.3MJ/g or roughly 300 Times the energy density fo TNT.
And that is ignoring energy required to compress the protons to a sphere with a noninfinite radius.
Which is orders of magnitude higher than the ionization energy.
Also, the total ionization energy is quadratic in Z, so even light atoms like carbon and oxygen have ionization energy dozens of times higher than hydrogen.
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The first ionization energy of carbon is 11.26 eV, but when you get down to the last
drop K-shell electron, the required energy is, indeed, huge.
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Well it's a sci-fi weapon, a disintegrator ray. In Niven's novels there's the "digger", that doesn't remove electrons but cancels their charge so the target violently flies apart. (What the weapon emitter is made of is anyone's guess). In one story they come up with a matching weapon that cancels the charge on the proton and they fire both beams in parallel at a planet's surface.
I think Niven described the result as "there will be a current" that looks like a 12 mile long bar of solid lightning. :scared:
Funny stuff.
I wouldn't even know how to begin looking for how it would be physically possible to cancel the charge of a fundamental particle like the electron. The proton seems to be made of three quarks that are constantly flipping around and maybe a beam of weird particles can force a preferred configuration of a proton that would have more or less charge. Shrinking atoms or prying them apart, oh my.
Even more sci-fi fun are fictional non-nuclear super-materials that simply don't react to said beams. Cuz they're like made of gluons only or space-time distortions. Like a cosmic string. :-DD
I love this stuff.