The binding energy of Li3

The Wigner–Seitz method provides a good effective potential, including correlation effects, for alkali molecules as well as metals. Here it is used with the matching Green function method to calculate the binding energy of linear Li3. This turns out to be −0.068 a.u. per molecule, relative to free atoms, at an equilibrium internuclear separation of 5.1 a.u., compared with −0.051 a.u. for the binding energy of Li2 obtained in a similar calculation.