"If you think that electrons have spins, then, I think, it's easy to explain the fine structure of the spectrum, as well as the anomalous Zeeman effect."

The Zeeman effect, a phenomenon in which the spectrum of an atom is divided into three in a magnetic field, was discovered by chance in 1896 by Peter Zeeman of the University of Amsterdam in the Netherlands.

Zeeman reported the phenomenon to his teacher, Lorenz, who explained it well with theory.

So in 1902, the two jointly won the Nobel Prize in Physics that year.

But a year after Zeeman discovered the effect that bears his name, experimental physicists discovered that sometimes the lines do not divide into three, but become multiple, with different intervals between the lines.

Therefore, the phenomenon of the division of spectral lines into three was called the normal Zeeman effect, and the other cases were called the abnormal Zeeman effect.

At this time, Lorenz, who was sitting in the C seat of the audience, was sandwiched between Rutherford and Marie Curie, and was very interested in the abnormal Zeeman effect mentioned by Chen Muwu in his discourse.

Because his theories could only explain the normal half, but could not do anything about the other half of the anomalous effects.

The theoretical explanation for this phenomenon has puzzled physicists today for more than 20 years.

Therefore, although Lorenz has retired, his attention is still attracted by Chen Muwu, and his mind is also carefully thought about according to his speech.

Even when he heard the rise, he raised his hand and asked, "Chen, you said that the rotation of electrons, oh no, spin, is so that the magnetic moment can be generated, right?" ”

"That's right, Professor Lorenz, that's why a spectrum splits into multiple strips in a magnetic field."

"So what is the specific value of this spin, is it one-half?"

"That's right, I think the spin angular momentum of the electron, positive should be plus or minus half of the Planck constant, and the positive and negative relationship in front satisfies the right-hand rule."

The reason why Lorenz knows that this value is one half is because as early as 1921, Professor Alfred Lande from the University of Tübingen in Germany was studying the anomalous Zeeman effect, and believed that the magnetic quantum number m, which describes the state of the electron, should not be taken as an integer, but should be followed by an integer.

But what exactly this half is, no one can say.

Now that Chen Muwu mentioned that electrons and spins can also produce magnetic moments, Lorentz naturally thinks of that tangled half.

Lorenz in the audience pondered for a while, and he began to make a qualitative semi-quantitative calculation in his mind, occasionally picking up a pen and writing and drawing on paper.

After a while, Lorenz spoke: "Chen, I think you may have made a big mistake on this issue this time. ”

"Please advise the professor."

Hearing that his proposed spin was denied by Lorenz, Chen Muwu was not only not surprised, but still full of confidence.

He even knew what Lorenz was going to say next.

"You say that the spin angular momentum of an electron is Planck's constant, then it is an order of magnitude of 10, and the spin angular momentum is the product of the mass of the electron, the velocity, and the radius, and the mass of the electron is 10 orders of magnitude, and the radius of the electron is 10 orders of magnitude.

"In this way, this electron 'equator', since you say that the electron rotates like the earth, then I will think that it also has an equator, and the linear speed on this equator should be 10 = 10 orders of magnitude, which is already hundreds of times greater than the speed of light of 10 orders of magnitude.

"However, according to Einstein's theory of relativity, there is no speed in the world that can exceed the speed of light, so following the data you gave, we get a wrong answer.

"This also shows that there can only be two situations for the truth of the matter, one is that the electron does not spin, and the other is that even if there is a spin, its value will not be the one you give, but should be much smaller than it."

"But I personally prefer the first option, which means that there is no such thing as spin in electrons."

After Lorenz finished speaking, the audience nodded along with him, showing that what the big guy said made sense.

No one is perfect, Chen Muwu has shocked the physics community for so long, there should always be a time to make a mistake, right?

Only Rutherford frowned slightly.

Because of more than a year of getting along, especially recently, Chen Muwu also personally designed experiments to prove the electronic wave theory that he originally thought was whimsical.

This made Rutherford already have some acquiescence in his heart, no matter what theory Chen Muwu proposed, it was basically accurate, he just had such a genius-like keen physical intuition.

Moreover, just now, when Chen Muwu introduced the property of electrons with spin, he also listed the atomic solar system model he proposed in the past.

When he heard this, Rutherford was still a little complacent, and it seemed that his model, which had been improved by Bohr, was not useless.

But Lorenz's words denied Chen Muwu's spin hypothesis, and he was a little embarrassed by the glory and the loss.

However, his own student in the stands still had his face unchanged and his heart did not beat, could it be that he had already thought of an answer to Lorenz's question?

Just as Rutherford thought, as soon as Chen Muwu heard Lorenz say that there was a problem with the electron spin, he immediately understood what the problem was, and gave a solution to the problem.

In fact, Samuel Goodsmitt and Georg Uhlenbeck, who proposed the spin theory, were just two students at Leiden University in the Netherlands.

Fascinated by Pauli's incompatibility principle, they came up with the concept of electron spin and submitted a paper of less than one page to their teacher, Paul Ehrenfest.

Ehrenfest had them publish their papers in the physics journal Nature, and at the same time wrote a letter to Lorenz, a respected man in the Netherlands, to introduce the new theory.

In his reply, Lorentz then rejects this new theory on the grounds that the linear speed of the electron spin exceeds the speed of light.

After Ehrenfest showed Lorenz's reply to the two students, they asked their teachers to write to the journal editorial office asking to retract the paper.

But it may be that Ehrenfest was lazy at this time, so he persuaded his two students, you are still young, and it is not a big problem to make a mistake in the journal and lose someone.

It was because of this reason of being lazy that the paper was finally published and the electron spin caused an uproar in the physics community.

Unexpectedly, now that Chen Muwu proposed the concept of electron spin at the Solvay Conference, Lorenz is still the first physicist to jump out and oppose the spin of electrons on the grounds that the speed of electrons is faster than the speed of light.

In fact, Chen Muwu has many ways to refute Lorenz's criticism, such as spin is actually an intrinsic property of particles, and it is not really like the earth is autobiography.

Or that the electron should not be seen as a solid spherical model, but as a point particle with no size, like a photon, and so on.

However, some of the above answers are too cumbersome to answer, and some involve too advanced knowledge.

At present, quantum mechanics has not really been established, whether it is Bohr or Sommerfeld, it is an atomic model constructed in the old quantum theory, that is, a semi-classical and semi-quantum way to deal with problems in the microscopic world.

Therefore, Chen Muwu can only choose to attack the shield of the son with the spear of the son, since Lorenz mentioned the matter of the theory of relativity, then it is good to still use the theory of relativity to fight back.

"Professor Lorenz, since you mentioned the theory of relativity, you also mentioned that if an electron had a spin, then its speed would exceed the speed of light.

"It's just that you forgot to think about the fact that at high speeds, the mass of the electron also changes, and the mass of the electron can no longer be calculated by the rest mass m, but by multiplying this mass by the Lorentz factor named after your last name, which is m = γm.

"As we all know, the higher the speed, the closer the γ is to zero. In this way, under high-speed conditions, the mass of the electron will also increase with the increase of velocity, and then calculate the speed of the electron, and it will be found that it does not exceed the speed of light, and it still conforms to the relativistic principle of the invariance of the speed of light. ”

The on-site physicists, including Lorenz, also felt that what he said was also very reasonable after listening to Chen Muwu's "justification".

"So, in addition to the anomalous Zeeman effect, can we devise an experiment to verify that electrons do indeed have the property of spin?"

Someone in the audience asked again.

There was no Einstein, no Bohr, and the audience was basically the leaders of the various labs.

Although the electron spin proposed by Chen Muwu may be a good explanation for the fine structure of the spectrum and the anomalous Zeeman effect, they always want to find a definite experiment that can completely prove that the electron does have spin.

"I'm very sorry, but I only thought of the fourth quantum number because I saw Stoner, a classmate from the Cavendish Laboratory, doing this experiment, and because Professor Ronde's research on Jewel was in front of me, I thought of the explanation that this half, could it be the spin of the electron.

"How do you design a new experiment to verify whether there is a spin in an electron? I'm sorry, but I don't have any specific thoughts or ideas on this issue at the moment. ”

After Chen Muwu finished speaking, he made a few concluding remarks on the stage, and finally completed his speech at this Solvay meeting.

Although the time was far more than the twenty minutes stipulated by the conference, no one on the scene cared about it.

After all, he proposed a fourth quantum number, which is already a major advance in the atomic model.

What's more, Chen Muwu once again couldn't stop talking - no one could count how many amazing theories he had put forward in the past year or so.

In the applause of everyone, Chen Muwu still returned to his own corner.

He didn't continue to listen to the next person's speech, and most of the people in the room were also absent-minded, thinking in their heads. It's just heard that the electron spin is being heard.

A few minutes later, Rutherford, with his pipe in his mouth, got up and left the table, as if he were going to smoke a bag of cigarettes outside the venue.

When passing by Chen Muwu's side, Rutherford inadvertently knocked on the corner of his table and motioned for Chen Muwu to go outside the venue with him.

(End of chapter)