Helium atom precision measurements and calculations have a history of nearly a century. In the 1960s, theorists discovered that the fine-structure split (23P0-23P2) of the 23P energy level of ...

More information: Nick A. von Jeinsen et al, 2D Helium Atom Diffraction from a Microscopic Spot, Physical Review Letters (2023). DOI: 10.1103/PhysRevLett.131.236202 ...

One is Na₂He, which consists of one helium atom and two sodium atoms ... 15 to 1.1 million times Earth's atmospheric pressure. Its structure should be similar to that of Na₂He, but in place ...

Save guides, add subjects and pick up where you left off with your BBC account. A helium atom has two electrons in an energy level outside the nucleus. The atom is neutral as it has two positive ...