Helium 4 Dimer in Two Coaxial Adjacent Nanotubes

The ground state properties of the helium 4 dimer, within the geometry defined by two adjacent nanotubes with different radii and hard core walls, are considered using the Monte Carlo technique. In this geometry, that may be realized as a generalization of a cylindrical one, the dependence of the binding energy on the radius leads to an effective force which moves the molecule towards the region of minimal energy. Thus, in tubes with non-homogeneous cross sections, the motion of particles is realized in dimer form.