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August 3, 2020

A new refrigerator for molecules

Sodium atoms (yellow spheres) collide with sodium-lithium molecules (combined-yellow-red-spheres). The atom-molecule mixture is trapped in an optical trap whose effective edge is shown as a white rim. As the trap is loosened (depicted as a dimmer rim), the most energetic sodium atoms leave the trap, providing evaporative cooling. The cooling is transferred to the molecules via elastic collisions. The frost on the molecules indicates that they have reached a temperature of 200 billionths of a degree Kelvin.

[Research supported by National Science Foundation grant PHY 1506369.]

Learn more in the MIT news story New 'refrigerator' super-cools molecules to nanokelvin temperatures. (Date image taken: unknown; date originally posted to NSF Multimedia Gallery: Aug. 3, 2020)

Credit: Figure by Pilsu Heo at Micropicture (South Korea) (Creative Commons CC BY-NC-ND 3.0)

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