For 80 years in a row "scientific mankind" has been struggling to create metallic hydrogen. It became literally a fix idea: to achieve the emergence of an ideal metal with superconductivity at room temperatures, the "filling" of the most powerful rocket fuel, the material for creating a "shield" from a neutron bomb.
The transition to the "metal stage" was substantiated back in 1935 by Eugene Wigner and Bell Huntington. They argued that at room temperature hydrogen will transform into a metallic form at a pressure of 25 GPa and begin to exhibit the properties of a superconductor. Since then, physicists who work with high pressures, it seemed that it is worth a little "addition", as the predicted will happen: hydrogen will become solid. However, the initially calculated pressure of 300 thousand atmospheres has already increased to five million, and metallic hydrogen has not yet been obtained.
Technically, it is practically impossible to achieve such a pressure on Earth, even in the core of our planet, the pressure does not exceed three million atmospheres. After the pressure “exceeded” a million, it became clear that we would have to take something hardest, for example diamonds, construct tongs from them and press, minimizing the point of application of force as much as possible. Such diamond vise was created, used by scientists from Harvard University (Isaac Silver, Thomas D. Cabot, Ranga Diaz) and managed to achieve the stage of metallic hydrogen, which was happily reported to the whole world in the journal Science.
And here's the bad luck: as soon as Isaac Silver and his colleagues were about to pull it out, one of the diamonds crumbled into "specks of dust", and the sample itself disappeared irrevocably - no one was able to find it. It sounds, of course, very intriguing, but in fact, as physicists say, there is nothing surprising in this. A pressure of five million atmospheres is precisely the ultimate strength of a diamond. When stress is removed, the chambers are destroyed quite often. One of the diamonds collapsed completely, and hydrogen, apparently, went into a gaseous state. It must be understood that we are talking about a microscopic dose of a substance. To get the "crazy" pressure, diamonds are sharpened and pressed into a metal gasket with a hole in the middle. Gas is pumped into a tiny space (10-50 microns). He was compressed to the state of metal, since, according to scientists,from transparent to opaque. The loss of transparency is the main criterion for the transformation of a gas into a metal.
The loss of the world's only sample of metallic hydrogen divided the world into two halves: one group of scientists believes that the sample with metallic hydrogen did exist, while others are increasingly inclined to believe that it was only the dream of an aging professor - Isa
Valentin Nikolaevich Ryzhov - Deputy Director for Science of the Institute of High Pressure Physics named after L. F. Vereshchagina, Doctor of Physical and Mathematical Sciences / Institute for High Pressure Physics named after L. F. Vereshchagin
Deputy Director for Science, Institute of High Pressure Physics LF Vereshchagina Valentin Nikolaevich Ryzhov, Doctor of Physics and Mathematics, is on the side of the optimists: “It looks like Isaac Silver got opaque hydrogen after all. But this could not be pure metallic hydrogen, but its semiconducting state. My colleague Mikhail Eremets, a former employee of our institute, also at one time received a semiconductor state of hydrogen, after which Isaac Silvera and the company wrote a letter refuting his discovery. Now that Silver has published his results, letters have appeared "in the opposite direction", which state that the experiments that he performed are not convincing enough to speak of a discovery on a global scale. I think that at the indicated pressures, metallic hydrogen could still arise,but it is not capable of being in a metastable state under normal conditions. Therefore, when Silvera wanted to take it out, the sample just went into gas."
But the head of the Department of Applied Mathematics of the National Research Nuclear University "MEPhI", Doctor of Physical and Mathematical Sciences Nikolai Alekseevich Kudryashov is inclined to believe that the whole story with Isaac Silver's metallic hydrogen is just a great desire, which is passed off as reality.
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Nikolay Alekseevich Kudryashov - Head of the Department of Applied Mathematics, National Research Nuclear University MEPhI, Doctor of Physics and Mathematics / NRNU MEPhI
“To be honest, I have no idea where on Earth you can take such a lot of pressure,” says Nikolai Kudryashov. - It is clear that theorists have calculated everything a long time ago, and at this pressure and the specified temperature, hydrogen should become metallic, however, as we know, theory and practice sometimes differ dramatically. Now most researchers are inclined to believe that this experiment was not clean. The important thing is that no one can repeat it, and “repeatability” is the main task in science”.
Nevertheless, Russian theoretical physicists from MEPhI, including Kudryashov himself, calculated that at a pressure of five million atmospheres and a temperature of minus 268 degrees Celsius, the phase of metallic hydrogen obtained by Diaz and Silver would be superconducting.
For the calculations, the Eliashberg system of equations was used, which most accurately allows one to determine the critical temperature for the transition of a substance to a superconducting state. The solution of this system made it possible to calculate the critical temperature of the transition of metallic hydrogen into a superconductor. However, it turned out that this temperature is much lower than room temperature and is equal to minus 58 degrees Celsius.
“Of course, such a temperature will not interfere with numerous technical applications of superconductors, but on condition that it is possible to obtain metallic hydrogen in large quantities. In the meantime, even the production of a small amount of metallic hydrogen still needs to be proved,”explained Kudryashov.
As for the professor at Harvard University Isaac Silver, he is currently making a new diamond vise to obtain metallic hydrogen.
Anna Urmantseva