The lowest energy 3Π2,1,0+,0− and 3Σ+1,0− excited states of the MgNe van der Waals molecule

We report ab initio calculations of the lowest 3Π and 3Σ+ excited states of the MgNe van der Waals molecule correlating with Mg(3s3p 3P0,1,2)+Ne(2p6 1S0). The spin–orbit multiplet potential curves of these states were estimated using the atomic spin–orbit coupling constant. Because of spin–orbit induced Σ/Π mixing, an extremely shallow potential curve is found for the lowest 3Π0− level (D0≈3 cm−1), perhaps explaining why we have been unable to prepare the Mg(3s3p 3P0)·Ne(3Π0−) state experimentally. The van der Waals bonding in the Mg(3s3pπ)·RG(3Π) states is compared with that in the analogous Na(3pπ)·RG[2Π] and Al(3s23pπ)·RG[2Π] states.