It is known from the physics course that, in addition to the "usual" scale of degrees Celsius, there is also the Kelvin scale, zero at which equals -273.15 degrees Celsius. At the same time, achieving this value is an extremely difficult task. Previously, scientists were able to cool individual atoms to the absolute zero temperature, but it was the first time to do this with a molecule.
According to the journal Nature Physics, physicists from the Center for Cold Matter managed to achieve a unique record. They cooled the substance to a millionth of a degree above absolute zero. Scientists succeeded in their research to approach the lowest possible temperature value. It is worth recalling that earlier in the course of a series of experiments, scientists were able to achieve only trillions of one kelvin, cooling individual atoms. To solve this problem, experts had to combine two traditional approaches.
Scientists used calcium fluoride molecules placed inside a magnetic-optical trap. Inside the trap, the substance was cooled with special lasers. In the course of this process, atoms absorb photons and "re-emit" them, spending more energy on it than is acquired. In such a simple way, you can lower the temperature only to a certain value (called the Doppler limit).
In order to overcome this limitation, physicists used a different method, consisting in using two moving toward each other laser beams. They "take" the excess kinetic energy of the molecule, cooling it to the desired value. Thanks to these manipulations, the temperature of the cooled molecules reached a 50-millionth degree degree from absolute zero. According to scientists, cooling to such ultra-low temperatures strongly slows down the molecules and allows more complete study of their properties and structure.
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