Molecular dynamics investigation of the configuration and shape of helium clusters in tungsten

The stable configuration and shape of a helium cluster in tungsten are investigated with the molecular dynamics method. It is found that the configuration of the helium cluster tends to form a near-spherical polyhedron. At a high temperature, the Hen cluster for n < 100 has enough time to evolve into a spherical structure even after coalescing between two helium clusters, while the large helium cluster could retain a rod-like or other shape for a long time. The formation mechanism of fuzz on tungsten surfaces is still unclear. Whether the shape of helium clusters is reasonable in simulations may have a significant effect on the formation of fuzz. Our results provide important references for Monte Carlo simulations.