Reborn and become a Great Scientist

Chapter 405 New spectral lines in the 144 spectrum

In any case, we still need to conduct the experiment first.

If the experiment is not successful at all, then there is no need to think about how to test the experimental product.

The Curies had polished off an oxide layer on the surface of the bismuth sample they borrowed from Uppsala University. Although it doesn't matter if they don't polish it, alpha particles can also bombard the bismuth atoms in bismuth trioxide.

But in order to reduce the impact of impurities, they decided to do it anyway, and it didn't cost much anyway.

Chen Muwu, Zhao Zhongyao and Cockcroft have also disassembled the proton source originally installed in the cyclotron center and installed the natural radioactive source borrowed from Uppsala University.

Fortunately, the radioactive source shutter that Chen Muwu created for the cyclotron model was still there, so it was installed as well.

Chen Muwu also pretended to install a cloud chamber behind the bismuth target after the alpha particles were emitted and bombarded, in order to detect whether the bombardment had bombarded anything from the bismuth.

Of course, something was indeed bombarded, but the trajectory of this new particle with a relative atomic mass of 1 and a charge of 0 cannot be displayed in the cloud chamber.

The cyclotron, which was turned on again, finally began to accelerate particles and conduct its first bombardment experiment after it was built by the five-person team.

Countless invisible accelerated alpha particles bombarded the visible bismuth metal target.

Everyone present did not hear the crackling sound like heavy rain hitting the window glass.

There is no need to observe with the naked eye whether the bismuth metal placed at the target position has undergone any chemical changes.

As time goes by, the first few photos of the cloud room have been developed as soon as possible.

But after looking at the trajectories recorded there, they were all high-energy alpha particles that had not bombarded the bismuth target, and the expressions on everyone's faces became even more disappointed.

Did Chen Muwu's experiment fail?

As he imagined, using high-energy alpha ions accelerated by a cyclotron to bombard the bismuth metal fixed on the target position would not yield the imaginary element No. 85.

Bismuth is a metal that has been discovered and used by people for a long time. It is speculated that the origin of its name may come from ancient German, which means "white metal".

But in fact, the color of pure bismuth metal is not necessarily pure white, but falls within the color range from silvery white to pink.

Before everyone did this experiment, they had already speculated on the iodine-like properties of element 85 that they might find.

Because fluorine is a light yellow-green gas, chlorine is a yellow-green gas, bromine is a dark reddish-brown liquid, and iodine is a purple-black solid...

The melting and boiling points of the first four halogen elements gradually increase, and the colors become darker and darker.

Therefore, everyone invariably speculated that this iodine-like element should also be solid, and its color should be deep black.

Therefore, in everyone's mind, if alpha particles bombard a bismuth metal target and produce new products, it should be easy to observe with the naked eye.

As long as black impurities are seen on the silver-white surface of the bismuth metal target, it means that the existence of iodine-like elements has indeed been produced through this bombardment experiment.

If it is not iodine-like, it would at least mean that a reaction did occur.

But the experimental results were just there without any obstruction. The bismuth metal was still the same bismuth metal, and the silvery white color was still the same silvery white color.

There may be some vague light yellow in some places, but that is not an iodine-like color, but the color of bismuth trioxide that has just not been polished or has just been generated.

Where did the black new halogen element iodine go?

Irena had a disappointed look on her face, as did her husband Frederick.

But when doing experiments, there are always successes and failures, and no one has smooth sailing every day.

Let's see what Chen Muwu plans to do next, maybe he can come up with new ideas.

Irena glanced at the other three people around her again. Chen Muwu's face was just calm and relaxed. Why did Zhao Zhongyao and Frederick have no expressions at all, and they did not regard Chen Muwu's failure as a coincidence. What's going on?

Chen Muwu estimated that enough time had passed since the bombardment, and planned to take out the bismuth metal on the target and conduct a test.

"Brother Zongyao, I think the experiment is enough to reach this point. What do you think?"

The family does not speak two languages. Facing Zhao Zhongyao, who is also from China, Chen Muwu naturally chose to speak Chinese.

Zhao Zhongyao also nodded: "I also think that time is enough. How about stopping the machine and let's see if there is a nuclear reaction on the target metal?"

"Okay, let's do it."

Irena and Frederic, who did not understand Chinese, could only worry on the side.

Fortunately, Zhao Zhongyao translated the general meaning of his words into English and told Frederick, another member of the group.

Does he still need to be tested?

There is no black iodine-like product on the silver-white surface of bismuth metal. The most intuitive phenomenon does not appear. How can it be tested?

Cockcroft removed the previously installed metal bismuth target from the target position of the cyclotron.

Chen Muwu knew that at this time, the metal bismuth target should have been enriched with a certain amount of iodine-like elements.

The half-life of these iodine-like elements is very short. From the moment they are produced, they begin to decay continuously, releasing alpha particles and releasing heat at the same time.

If the temperature of the bismuth target that has just passed through the metal is measured, it can be found that the temperature after the experiment is higher than the temperature before the experiment.

However, this phenomenon does not mean that iodine-like elements have been produced, because the accelerated alpha particles also carry a large kinetic energy, which can also be converted into the internal energy of the metal bismuth target after bombardment, thereby making the target temperature rises.

If the number of alpha particles bombarded on the target cannot be accurately measured, as well as the specific value of the temperature increase of the metal bismuth target, and the energy conversion efficiency between kinetic energy and internal energy, the phenomenon of temperature increase alone cannot explain this phenomenon. Iodine has been produced.

This simplest and most intuitive method is not applicable, but during the bombardment experiment, Chen Muwu had already thought of a good testing method, and it was the best one under the current experimental conditions.

--spectrum. Spectrum is one of the identification cards of chemical elements. Each element or its isotope corresponds to spectral lines of different wavelengths.

As long as a new spectrum can be detected, it can at least prove that they have indeed created something new by adding alpha particles to the cyclotron to bombard the bismuth element.

Under the command of Chen Muwu, Zhao Zhongyao smashed a small piece of metal bismuth target into several smaller particles, and then put them into a set of chemical equipment that had been built. Finally, he used an alcohol blowtorch to blast the equipment. The bismuth metal flask is heated to convert the bismuth metal into bismuth vapor, so that better spectral observations can be made.

By filling the metal vapor generated in this way into a vacuum tube with built-in electrodes, and then sealing it, a simple spectrum generating device is obtained.

Next, you only need to turn on the power, let the lamp made in the laboratory emit light, and then use the grating and spectrometer to detect other generated spectra. As long as new spectra that do not belong to the bismuth spectrum can be found in the spectrum, The spectral lines can at least show that their bombardment did produce new products other than bismuth-209.

In fact, if the chemical properties of iodine-like substances are indeed similar to iodine, Chen Muwuda can directly extract the heated iodine-like vapor with some organic or inorganic solvents, such as methanol, ethanol, chloroform and sodium hydroxide. etc., thereby separating the iodine-like element from the bismuth element and obtaining a solution with a higher iodine-like content.

But in general, it is most important to first detect whether a spectrum appears.

Among these five people, no one is a professional analytical chemist. Only Chen Muwu has done spectroscopic testing.

That was three years ago, at the David Faraday Laboratory of the Royal Institution in London, Chen Muwu used spectroscopy to detect the deuterium gas they separated from liquid hydrogen.

Therefore, this time the spectrum detection was also conducted by Chen Muwu.

Irena and Frederic gathered around Chen Muwu. In order to prevent the accuracy of his experiment from being affected, the Curies did not even dare to take a breath.

Chen Muwu easily saw the distribution of the spectrum in the eyepiece of the spectroscope.

Then he removed the eyepiece and replaced it with a camera that could take spectra.

Then they used this camera to record the spectrum of the "bismuth vapor" they obtained through sublimation on a glass imaging film.

The next step is to look for new spectral lines on the imaging film that should not appear in the "bismuth spectrum".

Any one of the five people could do this job, so Chen Muwu simply became the hands-off shopkeeper.

After comparing the spectral lines one by one, Zhao Zhongyao found a spectrum of 224.4 nanometers and another spectrum of 216.2 nanometers in the mid-ultraviolet region of the obtained spectrum. These two spectral lines happened to not exist in the "bismuth spectrum" New spectral lines.

Irena, who had been suppressed by the possible failure of the experiment since the beginning of this bombing experiment, finally had a smile on her face again.

Irena thought that the previous experiments conducted by Chen Muwu had easily succeeded, but she did not expect that the experiments would fail as soon as she and her husband participated.

Unexpectedly, when it came to the step of spectrum detection, there was a bright future, and everyone saw the hope that a new resentful woman No. 85 might exist.

The next step is to solve application problems and calculate which transition of which element corresponds to the two newly obtained spectral lines.

So the calculation became a test. Five people each had a piece of paper and a pen to see who could calculate it first.

Calculating spectral lines is actually a very boring job. It requires everyone to compare orbit by orbit. Especially for iodine-like element No. 85, which has many electron orbits outside the nucleus, the calculation workload is not small. .

Chen Muwu is one of those people who knows the answer in advance. He roughly estimated the time before announcing his result.

"These two spectral lines, I think, should be a transition from the 6p orbital to the 7s orbital. They may exist in a new element."

Chen Muwu didn't seem to be sure, and he didn't say anything conclusively.

After he "announced" his calculation results, the four people present verified the transition, and all came to conclusions that were consistent with the experimental results.

When everyone was happily preparing to celebrate, Chen Muwu suddenly poured a ladle of cold water on them.

"Let's check this spectrum again? After all, we only captured the spectral line once. These two spectral lines may also be affected by some accidental experimental errors."

Now that the bismuth vapor is ready, you only need to turn on the power of the spectral lamp, use the spectrometer to observe the spectral lines, and then take another photo.

In the spectral line photo recorded for the second time, there are also two spectra of 224.4 nanometers and 216.2 nanometers.

But compared with the first spectrum, the intensity of the two spectral lines in the second time was much weaker.

This means that the content of the new substance that produces these two spectral lines in the bismuth vapor is constantly weakening. The only possibility is...

"Decay! New matter is decaying rapidly!"

The other four people said almost in unison.

Next, Chen Muwu took the third and fourth spectral line photos. The intensity of the two spectral lines in these two spectral photos was also decreasing successively.

Through these four spectral line photos, it is almost certain that a new substance is indeed produced by bombarding a bismuth metal target with alpha particles accelerated by a cyclotron.

This substance has its own spectral lines and decays very quickly. Visually, the half-life should not be too long.

Frederick suggested: "Chen, I think we should compile this result into a paper immediately and publish it in relevant magazines."

Chen Muwu shook his head: "There's no rush. I think it's not the right time yet."

When it comes to the discovery of new elements, chemists react much like astronomers do when they hear about the discovery of new stars.

Astronomers must observe the sky according to the coordinates proposed by the discoverer and confirm that a new star that has never been recorded before has appeared. Only then will the discoverer's discovery be considered successful.

Chemists from all over the world also want to repeat the discovery process of others in their own laboratories to prove that what they discovered is not a new element.

Before Chen Muwu, element No. 85 had been "discovered" countless times by chemists around the world, and had been "falsified" countless times by chemists around the world.

No one wants to see others discover new elements, but they all want to discover new elements themselves.

(End of this chapter)