I've at least seen some QM equations, but I've not yet learned much of it. Going from the classical model of a neutral Hyrdogen atom, the electron orbiting like a planet, with it's outward inertia balancing the electric force inwards, what could be said of the orbit direction being cw or ccw. Is there a reason to distinguish between cw and ccw electron orbit ? If 2 macro sized charges were oribiting each other, and you had to describe the EM field, (which I can't fully yet) surely then you could easily say in the equations if the orbit is cw or ccw.


Is that what they call spin ? But then I know all particles are either 1/2 integer or integer spins, so it's not that simple. In the solar system model, did they have the electron spinning on it's own axis too ? like the spinning Earth ? That's how I remember thinking of spin, and I read a lot of laymen QM books growing up, but I don't remember a straight anwser on this. I know a magnetic field can separate charged paritcles into 2 groups, normally called spin up/down

Once you are in the QM orbital type model, is the whole 'probabliity shell' of the position of the electron....considered to be rotating in anyway akin to cw or ccw like the solar system model ?

What was the orbital speed in the old model ? Did they have a relativistic solar system model ?

I wish I knew where scienists hang out in my city.

 

You might find this useful:
https://www.antonine-education.co.uk/Pages/Physics_6/Phys_6_15/phys_6_Tut_15.htm

In classical terms 1 electron going round an atom in an orbit behaves like current in a solenoid, it produces a magnetic field. On the other hand if you have 2 electrons going in opposite direction, the magnetic fields they would generate cancel out, so there is no net observable effect.

 

Hello,

The spins also are used in NMR (Nuclear magnetic resonance).
You will see that C13 can be used for NMR and C12 not.

http://chem.ch.huji.ac.il/nmr/whatisnmr/whatisnmr.html

Bertus

 

The feature of partial differential equations that you need to get your head around is that there are often multiple solutions characterized by a set of discrete (quantized) values. The discrete values represent things like principle quantum number (energy level), angular momentum, orbital geometry (spatial location probability), and spin angular momentum. Spin is one of those things and you should think of as a way to distinguish particles from each other that can share the same energy level, rather than in a classical sense of a spinning top.

 

If 2 macro sized ch

If 2 macro sized charges were oribiting each other, and you had to describe the EM field, (which I can't fully yet) surely then you could easily say in the equations if the orbit is cw or ccw.

The direction of the spin would depend on which side you were observing it from.
Regards,
Keith

 

Concepts of "Up" and "Down" have no meaning in the quantum world since gravity has very little effect on such small masses. Other forces are orders of magnitude larger at atomic distances.

 

Electrons have a spin even if they are not bound to a nucleus in an atom.

I have a degree in Physics, but I cannot come up with a definition of spin other than it is a property that can distinguish two otherwise identical electrons, and that two electrons with the same spin cannot occupy the same quantum state.

Bob

 

Electrons have a spin even if they are not bound to a nucleus in an atom.

I have a degree in Physics, but I cannot come up with a definition of spin other than it is a property that can distinguish two otherwise identical electrons, and that two electrons with the same spin cannot occupy the same quantum state.

Bob

The full name of the property is "spin angular momentum". Nobody said anything about electrons being bound. My answer was related to the properties of partial differential equations, and the sets of numbers that are used to characterize the solutions. The same principles apply to free electrons, or electrons in a crystal lattice, or in an N-channel.

 

Hopefully on topic, has the idea of quantum jumps been cast in doubt or discredited? That is, the random instantaneous movement of the electron within its orbit has been discounted by recent evidence?

 

Hopefully on topic, has the idea of quantum jumps been cast in doubt or discredited? That is, the random instantaneous movement of the electron within its orbit has been discounted by recent evidence?

https://physicsworld.com/a/to-catch-a-quantum-jump/

“Our experimental result shows that while quantum jumps are unpredictable and discrete (as Bohr thought) on long timescales, they can be continuous (as Schrodinger suggested) and predictable on a short time scale,” says Devoret.

Quantum jumps are not truly instantaneous and random
The researchers did not stop there: they also managed to control the quantum jump once it had started by applying an electric pulse to the artificial atom. In this way, they intercepted it and sent it back to the ground state. They are only able to do this because the quantum jump is not truly instantaneous and random. Instead, quantum jumps take the same trajectory between the two energy levels every time, so it is possible to predict how to send them back.

According to the Yale team, this is an important point: “while quantum jumps appear discrete and random in the long run, reversing a quantum jump means the evolution of the quantum state possesses, in part, a deterministic and non-random character,” say Devoret and Minev. “The jump always occurs in the same, predictable manner from its random starting point.”

 

The full name of the pro

The full name of the property is "spin angular momentum". Nobody said anything about electrons being bound. My answer was related to the properties of partial differential equations, and the sets of numbers that are used to characterize the solutions. The same principles apply to free electrons, or electrons in a crystal lattice, or in an N-channel.

Right I'm forgetting that electrons are still Ferimions even when alone.

I have a few graduate level QM text books thats I had since I was a clueless kid. And lots of pdf's on my PC. I'm in the process of going through my 1st year math and physics university books again, I do this for fun. But I hate getting stuck, but that's life.


So in the pictures of electron orbital's, like the p-shell, do they change in time,like rotate ? I've seen static pictures, but no movie of that, so IDK still.

 

Electrons have a spin even if they are not bound to a nucleus in an atom.

I have a degree in Physics, but I cannot come up with a definition of spin other than it is a property that can distinguish two otherwise identical electrons, and that two electrons with the same spin cannot occupy the same quantum state.

Bob

Yeah there's a lot of stuff that just arises from the majic of the math. I have to learn group theory and Lie algebra's, at least I know basic linear algebra already.

I've dabbled with tensors before, like covariant derivatives, but only symbolically, never with actual values, so I barely knew it. I have to do this stuff as a hobby NOW, otherwise, I'll be an old man starting.

 

Sounds like spintronics.
In ferromagnets, such as a bar magnets electron spins point in the same direction, up or down, thus providing collective strength to the materials. In antiferromagnets, the atomic arrangement is such that the electron spins cancel each other out, with half of the spins pointing in the opposite direction of the other half, either up or down. The electron has a built-in spin angular momentum, which can precess the way a spinning top precesses around a vertical axis.

 

“Our experimental result shows that while quantum jumps are unpredictable and discrete (as Bohr thought) on long timescales, they can be continuous (as Schrodinger suggested) and predictable on a short time scale,” says Devoret.

This seems contradictory to me but I guess it's just another of life's wonderful mysteries.

 

...
So in the pictures of electron orbital's, like the p-shell, do they change in time,like rotate ? I've seen static pictures, but no movie of that, so IDK still.

Since atoms by themselves are spherically symmetric it could be hard to tell. Remember, an orbital is the shape and location of a probability space where the electron has a high probability of being. For the s-orbital there is no way to determine the orientation of an atom. So we need to consider Beryllium with two 1s electrons, two 2s electrons, and a single 2p electron. This 2p electron can be in the 2px, or 2py, or 2pz orbital. Assuming you could observe things on an atomic scale in violation of the uncertainty principle, and saw that the 2p electron was in the x direction. A short time later you see it in the y direction. Now the question is did the atom change it's orientation or did the electron move from the 2px orbital to the 2py orbital. We don't know and what is worse, I don't think we have a way to find out. There is nothing about what I jest described that is forbidden as far as I know, since electrons outside the s-shells can have a positive non-zero probability of doing just about anything except diving into the nucleus.

 

My understanding (probably wrong as Hell)) is that a so called electron orbital is like a pendulum swinging across the diameter of an atom rather than whirling around a central nucleus. The electron travels as a wave which actually passes straight through the proton without being captured and sticking.

If the electron swings along two axis, it produces a Lissajous Figure. However, if it also swings through a perpendicular axis, it might produce some kind of sphere. Using the three dimensional concept, the potential and kinetic energy of the electron would be the sum of the energy in all three axis.

 

... The electron travels as a wave which actually passes straight through the proton without being captured and sticking.
...

This is true for the s-orbital only. There is a non-zero probability for the electron to be inside the boundary of the nucleus.
For the remaining orbitals the probability space excludes the nucleus. Remember, that as drawn, the orbitals do not prohibit and electron from jumping to the opposite lobe across empty space. The thing they show is where the electron is with a probability of 90%.