Isotopic separation of helium through graphyne membranes: a ring polymer molecular dynamics study

Microscopic-level understanding of the separation mechanism for two-dimensional (2D) membranes is an active area research due to potential implications this class various technological processes. Helium (He) purification from natural resources particular interest shortfall in its production. In work, we applied ring polymer molecular dynamics (RPMD) method graphdiyne (Gr2) and graphtriyne (Gr3) 2D having variable pore sizes He isotopes. We found that transmission rate through Gr3 many orders magnitude greater than Gr2. The selectivity either isotope at low temperatures a consequence delicate balance between zero-point energy effect tunneling $^4$He $^3$He. RPMD provides efficient approach studying isotopes, taking into account quantum effects light nuclei motions temperatures, which classical methods fail capture.