### Abstract

The four-component relativistic Fock space coupled cluster method is used to describe the magnetic hyperfine interaction in low-lying electronic states of the KCs molecule. Both diagonal and off-diagonal matrix elements as functions of the internuclear separation R are calculated within the finite-field scheme. The resulting matrix elements exhibit very weak dependence on R for the separations exceeding 8 Å, whereas in the vicinity of the ground-state equilibrium the deviation of molecular HFS matrix elements from the atomic values reaches 15%. The dependence of the computed HFS couplings on the level of core correlation treatment is discussed.

Original language | English |
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Article number | 137825 |

Journal | Chemical Physics Letters |

Volume | 756 |

DOIs | |

Publication status | Published - Oct 2020 |

### Scopus subject areas

- Physics and Astronomy(all)
- Physical and Theoretical Chemistry

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## Cite this

*Chemical Physics Letters*,

*756*, [137825]. https://doi.org/10.1016/j.cplett.2020.137825