The experiments were made possible by a novel, one-layer ion trap cooled to minus 269 C (minus 452 F) with a liquid helium bath.

实验利用了一种单层离子势阱，并将其浸在液氦浴中冷却到零下269摄氏度。

youdao

When you add this whole thing up, -411kJ/mol it gives you a net of minus 411 kilojoules per mole or about 4 eV per ion pair.

当你全部加上时，得到净能量,或者是4eV每个离子对。

麻省理工公开课 - 固态化学导论课程节选