Theoretical investigation of the a 3Σ+u, A 1Σ+u, c 3Σ+g, and C 1Σ+g potential energy curves of He2 and of He*(2 1S, 2 3S)+He scattering

Potential energy curves for the a 3Σ+u, A 1Σ+u, c 3Σ+g, and C 1Σ+g states of He2 are calculated using the MCSCF method. Comparison of the calculated dissociation energies and spectroscopic constants with the experimental values indicates that these are the most accurate theoretical curves reported to date for these states. The resulting curves are utilized to calculate the vibrational and rotational energy levels and to carry out He*(2 1S)+He(1 1S) and He*(2 3S)+He(1 1S) scattering calculations.