Electronic Spectra of Ytterbium Fluoride from Relativistic Electronic Structure Calculations

Abstract

We report an investigation of the low-lying excited states of the YbF molecule--a candidate molecule for experimental measurements of the electron electric dipole moment--with 2-component based multi-reference configuration interaction (MRCI), equation of motion coupled cluster (EOM-CCSD) and the extrapolated intermediate Hamiltonian Fock-space coupled cluster (XIHFS-CCSD). Specifically, we address the question of the nature of these low-lying states in terms of configurations containing filled or partially-filled Yb $4f$ shells. We show that while it does not appear possible to carry out calculations with both kinds of configurations contained in the same active space, reliable information can be extracted from different sectors of Fock space--that is, by performing electron attachment and detachment IHFS-CCSD and EOM-CCSD calculation on the closed-shell YbF${}^{+}$ and YbF${}^{-}$ species, respectively. From these we observe $\Omega =1/2,3/2$ states that arise from the $4f^{13}{\sigma }_{6s}^2$, $4f^{14}5d$/$6p$, and $4f^{13}5d{\sigma }_{6s}$ configurations appear in the same energy range around the ground-state equilibrium geometry and they are therefore able to interact. As these states are generated from different sectors of Fock space, they are almost orthogonal and provide complementary descriptions of parts of the excited state manifold. To obtain a comprehensive picture, we introduce a simple adiabatization model to extract energies of interacting $\Omega =1/2,3/2$ states that can be compared to experimental observations.

28+57 pages, 8+18 tables, 5+34 figures

References in corpus (7)

• All-Optical Formation of Quantum Degenerate Mixtures
• Perspective: Essentials of Relativistic Quantum Chemistry
• Methods for measuring the electron EDM using ultracold YbF molecules
• Relativistic EOM-CCSD for core-excited and core-ionized state energies based on the 4-component Dirac-Coulomb(-Gaunt) Hamiltonian
• Hyperfine structure constants on the relativistic coupled cluster level with associated uncertainties
• Fock space relativistic coupled-Cluster calculations of Two-Valence Atoms
• Relativistic multi-reference Fock-space coupled-cluster calculation of the forbidden $6s^2^1 S_0 \longrightarrow 6s5d^3 D_1$ magnetic-dipole transition in ytterbium

Cited by in corpus (3)

• Benchmarking of the Fock space coupled cluster method and uncertainty estimation: Magnetic hyperfine interaction in the excited state of BaF
• Direct observation of the Yb(4f13 6s2)F states and accurate determination of the YbF ionization energy
• Theoretical study of the I${}^{+}$ + I${}^{-}$ mutual neutralization reaction