Potential curves for the ground states and some excited states of MgNe, Mg+Ne, and Mg+2Ne van der Waals complexes

Abstract

We have estimated the potential curves of the Mg(3s2)⋅Ne(1Σ+), Mg(3s3p)⋅Ne(3Π,3Σ+), Mg(3p2)⋅Ne(3Σ−), Mg+(3s)⋅Ne(2Σ+), Mg+(3p)⋅Ne(2Π), and Mg+2(2p6)⋅Ne(1Σ+) van der Waals states by means of ab initio calculations. Similar to the analogous doubly-excited states of MgAr and MgKr, the Mg(3pπ3pπ)⋅Ne(3Σ−) state is found to be unusually strongly bound, De=548 cm−1, a bond strength which is more than 20 times that of the singly-excited Mg(3s3pπ)⋅Ne(3Π) state and even more than three times that of the Mg+(3s)⋅Ne ion. The strong bonding is attributed primarily to the lack of a Mg(3s) electron, so that all the attractive van der Waals forces can extend to smaller internuclear distances because there is no Mg(3sσ)/Ne(2pσ) exchange repulsion.