Binding of two helium atoms in confined geometries

We carry out a comprehensive study of the binding of two helium atoms in un restricted and, in particular, in restricted geometries in both two and thr ee dimensions. Besides the well known binding of the He-4 dimer in unrestri cted geometry in two and three dimensions, Ile also find weakly bound state s of the He-3-He-4 molecule and the He-3 dimer in 2 dimensions. Furthermore , any combination of two He-4 or He-3 atoms can form a molecule if their mo tion is sufficiently confined. Our calculations ar-e carried out by numeric ally solving the Schrodinger equation as well as by constructing a suitable variational wave function.