Physical Review Letters
Stability of Small Mixed Clusters of H4e and H3e Atoms
R. Guardiola, Jesús Navarro
Abstract
The existence of small helium clusters containing a variable number of $^{\mathrm{4}}\mathrm{H}\mathrm{e}$ and $^{\mathrm{3}}\mathrm{H}\mathrm{e}$ atoms is studied within a variational Monte Carlo calculation employing the Aziz HFD-B(HE) pair interaction. The clusters ${^{\mathrm{4}}\mathrm{H}\mathrm{e}}_{2}$ support one and two $^{\mathrm{3}}\mathrm{H}\mathrm{e}$ atoms; however, the system with three $^{\mathrm{3}}\mathrm{H}\mathrm{e}$ atoms is metastable, and the next bound system requires at least 18 fermions. All clusters obtained by adding $^{\mathrm{3}}\mathrm{H}\mathrm{e}$ atoms to the trimer ${^{\mathrm{4}}\mathrm{H}\mathrm{e}}_{3}$ and the tetramer ${^{\mathrm{4}}\mathrm{H}\mathrm{e}}_{4}$ are bound, but the clusters ${^{\mathrm{4}}\mathrm{H}\mathrm{e}}_{3}$-${^{\mathrm{3}}\mathrm{H}\mathrm{e}}_{3,4,5}$ and ${^{\mathrm{4}}\mathrm{H}\mathrm{e}}_{3,4}$-${^{\mathrm{3}}\mathrm{H}\mathrm{e}}_{9}$ are metastable. All remaining clusters with three or more bosons and any number of fermions are stable.