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

The low-lying electronic states of ThF+, a possible candidate in the search for P- and T -violation, have been studied using high-level correlated relativistic ab initio multi-reference coupled-cluster and configuration interaction approaches. For the ³Δ state component with Ω= 1 (electron electric dipole moment ‘science state’) we obtain an effective electric field of E_eff = 35.2 GV cm⁻¹, a P- and T-odd electron–nucleon interaction constant of W_P,T = 48.4 kHz, a magnetic hyperfine interaction constant of A_∥ = 1833 MHz for ²²⁹Th (I = 5/2), and a very large molecular dipole moment of 4.03D. The Ω= 1 state is found to be more than 300 cm⁻¹ lower in energy than Ω = 0⁺ (¹Σ⁺), challenging the state assignment from an earlier theoretical study on this species (Barker et al 2012 J. Chem. Phys. 136, 104305).