The local spin dynamics of the electron is studied from the viewpoint of the electric dipole moment (EDM) of the electron in the framework of the quantum field theory. The improvements of the computational accuracy of the effective electric field $\left({\mathcal{E}}_{\mathrm{eff}}\right)$ for the EDM and the understanding of spin precession are important for the experimental determination of the upper bound of the EDM. Calculations of ${\mathcal{E}}_{\mathrm{eff}}$ in YbF $\left({}^2{\mathrm{\Sigma }}_{1/2}\right)$, BaF $\left({}^2{\mathrm{\Sigma }}_{1/2}\right)$, ThO $\left({}^3{\mathrm{\Delta }}_1\right)$, and ${\mathrm{HF}}^{+} \left({}^2{\mathrm{\Pi }}_{1/2}\right)$ are performed on the basis of the restricted active space configuration interaction approach by using the four-component relativistic electronic structure calculation. The spin precession is also discussed from the viewpoint of local spin torque dynamics. We show that a contribution to the torque density for the spin is brought into by the EDM. Distributions of the local spin angular momentum density and torque densities induced by external fields in the above molecules are calculated and a property related with large ${\mathcal{E}}_{\mathrm{eff}}$ is discussed.

• Received 14 October 2015

DOI:https://doi.org/10.1103/PhysRevA.93.012518