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Charge radius rms


Butch

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because there is no definite boundary to the nucleus, the electrons "see" a range of cross-sections, for which a mean can be taken. The qualification of "rms" (for "root mean square") arises because it is the nuclear cross-section, proportional to the square of the radius, which is determining for electron scattering

https://en.wikipedia.org/wiki/Charge_radius

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2 minutes ago, studiot said:

No, do you have a reference?

 

I was investigating charge radius in relation to my atomic model (if an electron falls... I think you are familiar with it. I had been referring to it as the nuclear area. When I search for info on charge radius of the nucleus everything I find gives an rms value(try it yourself), note that in my model the charge radius would oscillate.

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I said most clearly that it is not oscillating.

What part of No did you not understand?

 

Edit I don't know why Strange didn't actually answer your question since that was his alleged purpose.

Edited by studiot
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6 minutes ago, Strange said:

So we are not saying that it is not oscillating, just hasn't been an issue and we assume it is not?

 

Just now, studiot said:

I said most clearly that it is not oscillating.

What part of No did you not understand?

Just asking wether it was an assumption or a deduction...

Strange I ached for your input on my topic "if an electron falls through the nucleus..." In speculations, but alas.

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8 minutes ago, Butch said:

So we are not saying that it is not oscillating, just hasn't been an issue and we assume it is not?

No. It is not oscillating. There is no evidence it is oscillating. There is no theoretical reason to think it is oscillating.

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4 minutes ago, studiot said:

I answered your question,

but you have yet to answer mine.

you have not posted a single reference - I only asked for one.

https://www.google.com/url?sa=t&source=web&rct=j&url=http://iopscience.iop.org/article/10.1088/0305-4616/11/8/008/pdf&ved=0ahUKEwjtqJjg2JnYAhVHLyYKHWkHAWEQFghHMAQ&usg=AOvVaw2_TPljdyRH_kgLLXEZydWd

Actually, my first source was the isotope browser app on my phone, then I began surfing the web.

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Thank you.

Here is a more complete extract from the Wiki article that Strange linked to (and I had also found but not quoted).

Quote

The problem of defining a radius for the atomic nucleus is similar to the problem of atomic radius, in that neither atoms nor their nuclei have definite boundaries. However, the nucleus can be modeled as a sphere of positive charge for the interpretation of electron scattering experiments: because there is no definite boundary to the nucleus, the electrons "see" a range of cross-sections, for which a mean can be taken. The qualification of "rms" (for "root mean square") arises because it is the nuclear cross-section, proportional to the square of the radius, which is determining for electron scattering.

The root mean square value of something is a statistical method of deriving an average or mean value from a range.

It is used in sine wave curves in power engineering for AC current, but it is also used much more widely when we want an average for a function that is varying, but not oscillating.

In the case of the nucleus charged particles approaching the nucleus are deflected away in their path. This is called scattering.

The RMS radius gives us the size of a standard sphere of evenly distributed charge that would effect the same deflection scattering as is observed.

This is similar to saying the RMS current is the value of DC current that has the same heating effect as a given AC current.

There is, of course, theory to attempt prediction of this radius size look in

 

Rutherford, Chadwick and Ellis : Radiations from Radioactive substances chapters 2 and 8. : Cambridge University Press.

Since they did the original reasearch (1930) starting with alpha particles as well as the ebta particles mentioned by Wiki.

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5 minutes ago, Butch said:

Not charges, charge radius of a nucleus. 

The Radius of charge does not change unless a charge  is added or removed, which would still require a decay reaction, the Radius of charge is a function of Magnitude of charge. 

Edited by Vmedvil
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6 minutes ago, studiot said:

Thank you.

Here is a more complete extract from the Wiki article that Strange linked to (and I had also found but not quoted).

The root mean square value of something is a statistical method of deriving an average or mean value from a range.

It is used in sine wave curves in power engineering for AC current, but it is also used much more widely when we want an average for a function that is varying, but not oscillating.

In the case of the nucleus charged particles approaching the nucleus are deflected away in their path. This is called scattering.

The RMS radius gives us the size of a standard sphere of evenly distributed charge that would effect the same deflection scattering as is observed.

This is similar to saying the RMS current is the value of DC current that has the same heating effect as a given AC current.

There is, of course, theory to attempt prediction of this radius size look in

 

Rutherford, Chadwick and Ellis : Radiations from Radioactive substances chapters 2 and 8. : Cambridge University Press.

Since they did the original reasearch (1930) starting with alpha particles as well as the ebta particles mentioned by Wiki.

So in my understanding, since the charge of the nucleus while more or less spherical it is not consistent in strength(inverse square) so the rms value assigns a radius that allows us to predict electron scattering... Have I got it?

I at least understand now that it is not rms as in a sine wave.

Thanks.

5 minutes ago, Vmedvil said:

The Radius of charge does not change unless a charge  is added/removed, which would still require a decay reaction.

I agree, what I am looking for is what happens when electrons fall through the nucleus, I know probability says they can't but the model I am working on allows this without violating qm probability.

Edited by Butch
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5 minutes ago, Butch said:

So in my understanding, since the charge of the nucleus while more or less spherical it is not consistent in strength(inverse square) so the rms value assigns a radius that allows us to predict electron scattering... Have I got it?

I at least understand now that it is not rms as in a sine wave.

Thanks.

I agree, what I am looking for is what happens when electrons fall through the nucleus, I know probability says they can't but the model I am working on allows this without violating qm probability.

What Via quantum tunneling? 

barr.gif

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6 minutes ago, Butch said:

So in my understanding, since the charge of the nucleus while more or less spherical it is not consistent in strength(inverse square) so the rms value assigns a radius that allows us to predict electron scattering... Have I got it?

I at least understand now that it is not rms as in a sine wave.

Thanks.

Yes more or less.

Don't forget that this is not the 'real' knobbly nucleus it is an 'equivalent sphere' that has the same total charge evenly distributed all over.

Also not only electron (beta particles) scattering but also positive particle scattering (alpha particles).

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Just now, Vmedvil said:

What Via quantum tunneling? 

barr.gif

No, less complex, my model needs refinement and formulae. If you wish take a peek here http://www.scienceforums.net/topic/112223-if-an-electron-falls-through-the-nucleus-of-an-atom/?page=5

 

3 minutes ago, studiot said:

Yes more or less.

Don't forget that this is not the 'real' knobbly nucleus it is an 'equivalent sphere' that has the same total charge evenly distributed all over.

Also not only electron (beta particles) scattering but also positive particle scattering (alpha particles).

Thanks!

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5 minutes ago, Butch said:

Thanks!

You should also be aware that more exotic processes give broadly similar but different values (smaller) for the nuclear radius.

for example

Rainwater and Fitch

Hofstadter

etc

 

However  this makes quite a difference to the nucleon density since the volume is proportional to the cube of the radius.

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No I agree, with Swan(Which is a rarity) that model is wrong the Spinor you generated is impossible in "Real Universe" always around the center of mass or charge in this case not through it. 

IMG_20171216_143123.thumb.jpg.1197b98eab164424f6561c37ebe36d22.jpg.94b9e47fc7f493a74c30abc1313a9a99.jpg

 

Edited by Vmedvil
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4 minutes ago, studiot said:

You should also be aware that more exotic processes give broadly similar but different values (smaller) for the nuclear radius.

for example

Rainwater and Fitch

Hofstadter

etc

 

However  this makes quite a difference to the nucleon density since the volume is proportional to the cube of the radius.

You understand why this interests me, I assume?

3 minutes ago, Vmedvil said:

No I agree, with Swan(Which is a rarity) that model is wrong the Spinor you generated is impossible in "Real Universe" always around the center of mass not through it. 

IMG_20171216_143123.thumb.jpg.1197b98eab164424f6561c37ebe36d22.jpg.94b9e47fc7f493a74c30abc1313a9a99.jpg

 

Fair enough. Swan has helped me a great deal, If he hits me with something I take it to heart. His knowledge is quite reliable in my opinion.

Edited by Butch
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4 minutes ago, Vmedvil said:

 

Here is a correct spinor of a S orbital 

main-qimg-f2687345bc7bb7fe85f2b6d6619fd42b.png.d42d8378a906e8586cfc8673fa5c7eac.png

 

Did you understand my concept of sister electrons? This post indicates some insight... But perhaps not complete? For example the sum of vectors?

Edited by Butch
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