An accurate ab initio calculation on potential of the ground states of the He and Li atoms

Potential energy curves of the groundstate of the He-Li system are determined by using efficient basis set 6-311 + + G(3df, 3pd) augmented with midbond functions {3s3p3d2f} at the MP4SDTQ, QCISD(T) and CCSD(T) levels, The full counterpoise (FCP) method is applied for the BSSE correction, Our calculations indicate a well depth of about (7.0 +/- 0.4) X 10(-6) a.u. at the around r(e) = 11.6 a.u. The results are in very good agreement with Das and Wahl's MCSCF values, but differ in the experimentally determined model potentials for well,depth deduced by Dehmer and Wharton.