Theoretical study on ThF+, a prospective system in search of time-reversal violation

Abstract

The low-lying electronic states of ThF ^+ , a possible candidate in the search for $\mathcal{P}$ - and $\mathcal{T}$ -violation, have been studied using high-level correlated relativistic ab initio multi-reference coupled-cluster and configuration interaction approaches. For the $^{3}\Delta $ state component with Ω = 1 (electron electric dipole moment ‘science state’) we obtain an effective electric field of ${{E}_{{\rm eff}}}=35.2$ ${\rm GV}\;{\rm c}{{{\rm m}}^{-1}}$ , a $\mathcal{P}$ - and $\mathcal{T}$ -odd electron–nucleon interaction constant of ${{W}_{P,T}}=48.4$ kHz, a magnetic hyperfine interaction constant of ${{A}_{\parallel }}=1833$ MHz for ^229 Th ( $I=5/2$ ), and a very large molecular dipole moment of 4.03 D. The Ω = 1 state is found to be more than 300 cm ^−1 lower in energy than $\Omega ={{0}^{+}}$ ( $^{1}{{\Sigma }^{+}}$ ), challenging the state assignment from an earlier theoretical study on this species (Barker et al 2012 J. Chem. Phys. http://dx.doi.org/10.1063/1.3691301 136 http://dx.doi.org/10.1063/1.3691301

Keywords

• electron electric dipole moment
• P, T symmetry violation
• relativistic electronic structure
• hyperfine interaction
• electronically excited states
• wavefunction theory