Potential energy curves of Li⁺₂ from all-electron EA-EOM-CCSD calculations

†In honour of Professor Sourav Pal on the occasion of an anniversary in his private and scientific life.

Abstract

The electron attachment (EA) equation-of-motion coupled-cluster theory provides description of the states obtained by the attachment of an electron to the reference system. If the reference is assumed to be a doubly ionised cation, then the EA results relate to the singly ionised ion. In the current work, the above scheme is applied to the calculations of the potential energy curves (PECs) of the Li⁺₂ cation adopting the doubly ionised Li^{2 +}₂ structure as the reference system. The advantage of such computational strategy relies on the fact that the closed-shell Li^{2 +}₂ reference dissociates into closed-shell fragments (Li^{2 +}₂ ⇒ Li⁺ + Li⁺), hence the RHF (restricted Hartree–Fock) function can be used as the reference in the whole range of interatomic distances. This scheme offers the first principle method without any model or effective potential parameters for the description of the bond-breaking processes. In this study, the PECs and selected spectroscopic constants for 18 electronic states of the Li⁺₂ ion were computed and compared with experimental and other theoretical results.

Keywords:

• electron affinity
• potential energy curves
• equation-of-motion coupled-cluster method
• lithium dimer cation
• spectroscopic constants

Acknowledgements

This work has been supported by the National Science Centre, Poland under grant no. 2013/11/B/ST4/02191.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

†In honour of Professor Sourav Pal on the occasion of an anniversary in his private and scientific life.

Additional information

Funding

This work has been supported by the National Science Centre, Poland [grant number 2013/11/B/ST4/02191].