Solidification of helium, at room temperature under high pressure

Abstract

Melting of 4He has been observed at 297 K and 115 ± 2 kilobars. This value is close to that derived from Simon's equation, extrapolated from 5 kilobar data. The diamond cell we used is a new design and allows inert gases to be studied between 4 and 500 K up to 1 megabar.