Comment by varenc

I really have no idea...but I don't think so! Or at least if the kinetic diameter is the smallest hole something can fit through it can't?

Helium's is 260pm or 0.26nm so that could be the limit. But the actual atomic diameter has a couple different calculated and observed values from 31pm to 140pm so maybe it could fit through holes around that size? My guess is we don't have the technology to make a hole of precisely that size or even measure a single He atom passing through such a hole. Would probably have to find a real expert to know if it's theoretically possible.