A calculation of the well depth for a pair of helium atoms

A new methods is proposed for the elimination of the basis superposition error in the calculation of small potentials. The method which involves CI is applied to the calculation of the well depth of He₂. It includes interatomic and intraatomic correlation effects simultaneously. A value for the well depth of 10.54 K at R = 3.03 au is obtained, in excellent agreement with current theoretical estimates.