Abstract
The energy gained by either of the two helium atoms in a helium dimer through simultaneous ionization and excitation can be ef?ciently transferred to the other helium atom, which then ionizes. The respective relaxation process called interatomic Coulombic decay (ICD) is the subject of the present paper.
In this work, we present the relevant potential-energy curves and the interatomic decay widths. The full-con?guration interaction method was used to obtain the potential energy curves.
The decay widths were computed by utilizing the Fano ansatz, Green's-function methods, and the Stieltjes imaging technique. The behavior of the decay widths with the interatomic distance is examined and is elucidated, whereby special emphasis is given to the asymptotically large interatomic separations.
Our calculations show that the electronic ICD processes dominate over the radiative decay mechanisms over a wide range of interatomic distances.