why Nuclear Physics cannot be entirelly correct

[Tubbythin]

Since you have the book, it makes pedrone's task about citations even easier. While he is working from a Portuguese version of the book, the page numbers should be roughly the same.

Suprisingly not. The pages he quotes as pages 685 and 686 I appear to have (or at least the diagrams correspond to) pages 547 and 548.

 

[Nihilianth]

Now I won't be able to read your responses to Pedrone, I quite enjoyed them.
You are just doing this to be mean to me, it's not fair, wheehehehehe.

Oh, hi Pedrone.

I'm quite touched! I really am!

*sobs*

*runs away!*

 

[Nihilianth]

To be honest, I have no idea what he is talking about...
Eisberg and Resnick - Quantum Physics of Atoms, Molecules, Solids, Nuclei and Particles, 2nd Edition, p541:

And that would be the actual ENGLISH version, written either by expert linguists (if the book was originally written in a different language altogether) or written by Eisberg and Resnick themselves, and edited by a professional editor, and published by a professional publishing house, I presume? Not a Portuguese version that you have decided to translate all by yourself?

 

[Daylightstar]

I'm quite touched! I really am!

*sobs*

*runs away!*

That bad eh?

These two smileys doesn't make it Pedrone-esk I trust.

 

[pedrone]

Wow !!

Magic numbers happen to be even. But even unmagic nuclei are stable, e.g. 18O has 2 excess ("paired") neutrons.

This is absurd.
¹⁸O cannot have 2 paired neutrons.

¹⁸O has:
- null nuclear magnetic moment M=0
- null electric quadruople moment EQM=0

¹⁸O with 2 paired neutrons never could have M=0 and EQM=0

 

[Reality Check]

This is absurd.
¹⁸O cannot have 2 paired neutrons.

¹⁸O has:
- null nuclear magnetic moment M=0
- null electric quadruople moment EQM=0

¹⁸O with 2 paired neutrons never could have M=0 and EQM=0

This is absurdly ignorant.
¹⁸O can have 2 paired neutrons. Neutrons can have opposite spin. "Paired" neutrons will have opposite spins (that is the whole point of the shell model!). Their spins will add up to zero.

¹⁸O has:
- zero nuclear magnetic moment M=0
- zero electric quadruople moment EQM=0

¹⁸O with 2 paired neutrons could have M=0 and EQM=0

 

[Reality Check]

Suprisingly not. The pages he quotes as pages 685 and 686 I appear to have (or at least the diagrams correspond to) pages 547 and 548.

Pity - that means that pedrone will have to quote enough of the text to identify it in the book.

 

[pedrone]

This is absurdly ignorant.
¹⁸O can have 2 paired neutrons. Neutrons can have opposite spin. "Paired" neutrons will have opposite spins (that is the whole point of the shell model!). Their spins will add up to zero.

¹⁸O has:
- zero nuclear magnetic moment M=0
- zero electric quadruople moment EQM=0

¹⁸O with 2 paired neutrons could have M=0 and EQM=0

The problem is not with spin.
Two paired neutrons will concentrate their mass in one point of the nucleus.

Although neutrons have null electric charge, however they have magnetic moment.
So, with the spinning of the nucleus ¹⁸O, such magnetic moment of the two neutrons, concentrated in one point of the nucleus, will produce a big nuclear magnetic moment of ¹⁸O, since the two neutrons are turning about the center of the nucleus.

In order ¹⁸O to have a null nuclear magnetic moment, the two neutrons have to take opposite places, with contrary direction of their vector magnetic moment.

Also, the two neutrons concentrated in one place will unballance the distribution of masses, and the nucleus will vibrate (trembling motion), and the ¹⁸O could not have null electric quadrupole moment

 

[pedrone]

Pity - that means that pedrone will have to quote enough of the text to identify it in the book.

I'm not in my house, where my book is.]

In the end of the week I'll go there. I will scan the page, and as there are figures there, it will be easy to find the page.

 

[Reality Check]

The problem is not with spin.
Two paired neutrons will concentrate their mass in one point of the nucleus.

The problem is that you are wrong.
The two "paired" neutrons are in the outer orbital of the nucleus. The inner orbitals are filled by the other nucleons.

Their mass is not concentrated anywhere. They are not at any one point. That is where those dumb cartoons are fooling you. This is a QM system. There is only a probability of the 2 neutrons being at a point in the orbital at any one time. The probability of them being at one point at the same time is small.

The only "pairing" is via the Pauli exclusion principle. That is that the nucleons have to different states. They are in the same orbital. They have to have different spins. To get the total spin you just add the spins. Thus there is zero spin and zero magnetic moment.

ETA: A bit of English for you. If a word is in quotation marks, e.g. "paired", then the word is being used in a looser context then it is usually used. Paired has the context that 2 things are close together. "Paired" has a looser context, i.e. that the objects are connected in some way but need not be physically close together.

 

[pedrone]

The problem is that you are wrong.
The two "paired" neutrons are in the outer orbital of the nucleus. The inner orbitals are filled by the other nucleons.

This is worst.
Two paired neutrons in the outer orbital will have a biggest radius or spinning, and so stronger will be the ¹⁸O nuclear magnetic moment

 

[pedrone]

Their mass is not concentrated anywhere. They are not at any one point. That is where those dumb cartoons are fooling you. This is a QM system.

Sorry,
but such argument imply the following: we can consider that all nucleons, within all the nuclei, are not concentrated anywhere, they are not at any point.

CONCLUSION:
all nuclei ought to have:
- null nuclear magnetic moment
- null electric quadrupole moment

Then I dont understand why Aage Niels Bohr proposed the Collective Model, used to calculate nuclear magnetic moments and electric quadrupole moments.

After all, according to your argument all nuclei have:
- null nuclear magnetic moment
- null electric quadrupole moment

Reality Check,
you have to advise Aage Bohr that he is wrong

There is no need the Collective Model.

 

[Reality Check]

Sorry,
but such argument imply the following: we can consider that all nucleons, within all the nuclei, are not concentrated anywhere, they are not at any point.

That is correct - juts like electrons in atomic orbitals are not concentrated anywhere, neucleons in nuclei are not concentrated anywhere.

CONCLUSION:
all nuclei ought to have:
- null nuclear magnetic moment
- null electric quadrupole moment

You really are insisting on displaying your ignorance:
all nuclei ought to have:
- a zero or nonzero nuclear magnetic moment according to how the nucleon spins sum up. Nuclear Magnetic Moments
- a zero or nonzero electric quadrupole moment from the charge distribution of the nucleons in the nucleus. Electric Quadrupole Moments of Nuclei

Then I dont understand why Aage Niels Bohr proposed the Collective Model, used to calculate nuclear magnetic moments and electric quadrupole moments.

He proposed it as a combination of the liquid drop and shell models.

Perhaps you should tell him that you think that he is completely wrong. That you have the delusion that nucleons are stuck onto cartoon shapes, not in shells.

 

[Reality Check]

This is worst.
Two paired neutrons in the outer orbital will have a biggest radius or spinning, and so stronger will be the ¹⁸O nuclear magnetic moment

No this is the worst result of your ignorance .

The spin of the neutrons is a QM spin.

• They are not physically spinning like tops.
• It has nothing to do with any orbits.

Nuclear Spin
Nuclear Magnetic Moments

 

[The Man]

So, basically you are saying a Lagrange is a mathematical equation that is nothing but mostly variables (A, B, C, X, Y Z, etc) that one can plug numbers in, based on variable quantities, coordinates, or any other variable-type numbers given any particular theory or model?

Like in statistics...let's take baseball.....The statistic for Batting Average is:

H/AB, where H=number of Hits, and AB=number of At Bats.

Or VORP (Value Over Replacement Player,) the Lagrane would be:

(((League Runs/Game + 1) - RAvg)/9)*Innings Pitched

This means the number of runs per game in any given league = what how a replacement player would perform.

Take that number, and subtract the average Runs per 9 innings, and multiply the number of innings any particular player pitched (for pitchers). For hitters, it's slightly different.

Is that the idea?

Sorry I haven’t been able to reply sooner.


The Lagrangian is the general from of an equation (the kinetic energy less the potential energy) it isn’t an equation in and of itself as the variables involved can and do differ significantly depending on the application. Actually the sports analogy is not a bad way of thinking about it, so I’d like to expand on the sports analogy a bit to stress an important aspect of Lagrangian mechanics.

Baseball is a particular sport, as is hockey; similarly Cartesian coordinates are a particular coordinate system, as are polar coordinates. Just as hits and errors are a way of determining the performance of some athlete in the particular sport of baseball, shots and penalties does the same type of thing in hockey. Similarly X and Y coordinates represent a location in Cartesian coordinates while for polar coordinates it is angle and radius. For our ‘Lagrangian sports mechanics analogy’ factors of performance might be more akin to endurance, coordination and situational awareness. Variables that would be equally applicable to any sport not just some particular sport (our analogous equivalent of some particular coordinate system) or group of sports. I hope that makes sense to you or at least to someone other than just me.

 

[Nihilianth]

That bad eh?

These two smileys doesn't make it Pedrone-esk I trust.

Not quite. Barely, but not quite.

 

[Nihilianth]

For our ‘Lagrangian sports mechanics analogy’ factors of performance might be more akin to endurance, coordination and situational awareness. Variables that would be equally applicable to any sport not just some particular sport (our analogous equivalent of some particular coordinate system) or group of sports. I hope that makes sense to you or at least to someone other than just me.

OH, I get it! So a Lagrange is a set of...variables (for lack of a better term) that can fit any particular system. Like how reflexes, situational awareness, as you have said, speed, endurance, agility, etc; as variables; can fit any particular player, in any particular sport.

So, does that then mean that the Lagrange can translate how spatial bodies in outer space interact with one another, directly into how atoms and molecules interact with one another? If so, then I think I may be able to get some sort of handle on the whole conversation about "spin orbit interaction" that was being talked about earlier in the thread.

 

[The Man]

OH, I get it! So a Lagrange is a set of...variables (for lack of a better term) that can fit any particular system. Like how reflexes, situational awareness, as you have said, speed, endurance, agility, etc; as variables; can fit any particular player, in any particular sport.

Yep, though it's not a "Lagrange", which might be taken in reference to a Lagrange point (or a ZZTOP song) where the combined forces of multiple sources results in no net force on the body in consideration. It's the mechanics or Lagrangian mechanics that take into consideration both conservation of momentum and energy in a combined and coordinate system independent form.

So, does that then mean that the Lagrange can translate how spatial bodies in outer space interact with one another, directly into how atoms and molecules interact with one another? If so, then I think I may be able to get some sort of handle on the whole conversation about "spin orbit interaction" that was being talked about earlier in the thread.

Well there are scaling differences, on cosmological scales things tend to be dominated by gravity, as the only other long range force, electromagnetism, tends to cancel itself, at those scales. The problem with "spin" is that it is not the "spin" one considers in classical motion like an orbit but quantum mechanical "spin". A quantum aspect of particles that was given the name "spin" due to is directional analogy with rotational momentum. A matter of historical nomenclature that can unfortunately be a bit confusing. Much as certain quantum mechanical aspects of quarks have been given the names of "color", "flavor" and, strange as it may seem, "strangeness". While the forces other than gravity have been combined effectively into the standard model by Quantum Field Theory we as yet don't have a quantum theory of gravity. Though this does not stop QFT and the standard model from being an integral and significant element of modern cosmology.

 

[Tubbythin]

The problem is not with spin.
Two paired neutrons will concentrate their mass in one point of the nucleus.

No. A pair of neutrons in this sense means they have their total angular momentum (ie orbital plus spin) vectors anti-alligned. Hence, they have orbitals which are coplanar (or as near to coplanar as the Heisenberg uncertainty principle will allow) but rotate in opposite directions.

Although neutrons have null electric charge, however they have magnetic moment.
So, with the spinning of the nucleus ¹⁸O, such magnetic moment of the two neutrons, concentrated in one point of the nucleus, will produce a big nuclear magnetic moment of ¹⁸O, since the two neutrons are turning about the center of the nucleus.

But they're not, in general, concentrated at one point.

In order ¹⁸O to have a null nuclear magnetic moment, the two neutrons have to take opposite places, with contrary direction of their vector magnetic moment.

See above.

Also, the two neutrons concentrated in one place will unballance the distribution of masses, and the nucleus will vibrate (trembling motion), and the ¹⁸O could not have null electric quadrupole moment

Unbalance in what sense?

 

[Tubbythin]

And that would be the actual ENGLISH version, written either by expert linguists (if the book was originally written in a different language altogether) or written by Eisberg and Resnick themselves, and edited by a professional editor, and published by a professional publishing house, I presume? Not a Portuguese version that you have decided to translate all by yourself?

Well both authors worked at US universities at the time of writing so I'd imagine their English is fairly good, whether or not it is their mother tongue. Its published by John Wiley & Sons.