How many protons does H20 contain

health : Water is not H2O

Water is H2O, as every child knows: an oxygen atom is besieged by two hydrogen atoms. But now the school books have to be rewritten: water sometimes has not two, but only 1.5 hydrogen atoms. In experiments with very fast neutrons, Berlin researchers found out that a hydrogen atom makes itself partially invisible under fire. The proton shows wave properties as predicted by quantum theory.

So far, the “wave-particle dualism” has mainly come to light in the case of electrons. For atomic nuclei it has so far only played a subordinate role in chemistry. "The peak time between the neutrons of the bombardment and the proton of the hydrogen was in the order of magnitude between a billionth and a millionth of a billionth of a second," explains Aris Chatzidimitriou-Dreismann, researcher at the Technical University of Berlin. “In this attosecond range, the protons of the hydrogen atoms can obviously also adopt wave properties.” The simple model of one oxygen atom and two hydrogen nuclei no longer applies to this ultrafast observation.

All physics and chemistry are based on the idea that matter is made up of atoms. These in turn consist of a nucleus with a certain number of protons and neutrons around which electrons float. Electrons are negatively charged, protons are positive. Electric attraction holds the atom together.

At the beginning of the 20th century, the age of quantum physics began with Max Planck. Accordingly, the particles may also show the properties of waves. The electrons as particles are, for example, only at a certain point in the orbit around the atomic nucleus at any given time. In contrast, electrons as a wave can be found all over the orbit at the same time.

The physicist Erwin Schrödinger once described this paradoxical phenomenon with a cat that is both alive and dead. Schrödinger's cat is a zombie. Apparently the proton in the nucleus of the hydrogen atom too. For an unimaginably short time interval it ceases to be a solid particle and instead dissolves into a wave. This can result in a new type of quantum interference effect: the nucleus “disappears”.

“In the textbooks of chemistry or neutron physics, atomic nuclei are usually treated like classical particles,” says Aris Chatzidimitriou-Dreismann. "That can no longer be maintained." He had already predicted the effect in 1993. Two years later, the first experimental test was carried out on a spallation source at the Rutherford Appleton laboratory in England.

Such sources provide the fast neutrons that are needed for bombardment. The British neutron source is currently the most powerful in the world. The faster the neutrons are, the shorter the time intervals that can be measured. Because several researchers did not trust the measurement results, the experiment was repeated several times in recent years.

“Up to now, attosecond physics has hardly been researched,” explains the scientist. "But measuring the number of scattered neutrons leads to the conclusion that there are effectively 25 to 30 percent fewer protons in the water than would be expected from the conventional formula."

Recently, the physicist Maarten Vos of the Australian National University in Canberra did similar experiments in which he shot fast electrons at a polymer called Formvar. This plastic, a polyvinyl, is used, for example, as insulation for power cables. Its chemical structure also contains innumerable hydrogen atoms. In doing so, Vos made a discovery similar to that made by the experimenters in England. In Formvar, up to 50 percent of the protons even “squeezed out” as a result of their quantum nature.

Four years ago, scientists received a Nobel Prize for experimental studies with short-term lasers. Research is now on the new threshold to attosecond, which is about a thousand times shorter than the already tiny femtosecond.

“We presented the results of our experiments only a few weeks ago at the first conference on attosecond physics at Harvard University,” says Aris Chatzidimitriou-Dreismann. “This research area is brand new. We can be curious what surprises it will bring. "

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