Theoretical study of ThF$^+$ in the search for T,P-violation effects: Effective state of a Th atom in ThF$^+$ and ThO compounds

Abstract: We report the results of theoretical investigation of electronic structure of ThF$^+$ cation which is one of the most interesting systems to search for the electron electric dipole moment (eEDM) [H. Loh, K.C. Cossel, M.C. Grau, K.-K. Ni, E.R. Meyer, J.L. Bohn, J. Ye, E.A. Cornell, Science {\bf 342}, 1220 (2013)] and other effects of violation of time reversal (T) and spacial parity (P) symmetries in fundamental interactions. For the working $^3\Delta_1$ state we have found a quite high value of the effective electric field acting on unpaired electrons (37.3 GV/cm). The field will be required to interpret the experiment planed on ThF$^+$ in terms of eEDM. Within the concept of atoms in compounds [A.V. Titov, Y.V. Lomachuk, and L.V. Skripnikov, Phys. Rev. A {\bf 90}, 052522 (2014)] we have compared the ThF$^+$ electronic structure with that of ThO. Also we have calculated other parameters of T,P-odd interactions: $W_{T,P}$, which is needed for interpretation of the experiment in terms of the dimensionless constant $k_{T,P}$ characterizing the strength of the T,P-odd pseudoscalar$-$scalar electron$-$nucleus neutral current interaction (50 kHz); $W_M$, which is required to search for the Th nuclear magnetic quadrupole moment in $^{229}$ThF$^+$ (0.88 $\frac{10^{33}\mathrm{Hz}}{e {\rm cm}^2}$). A number of properties which can be measured are also calculated: hyperfine structure constant, the molecule-frame dipole moment, and g-factor.