Search for an Electric Dipole Moment in Thallium

The atomic-beam magnetic-resonance technique has been used to search for a linear Stark effect, which would violate parity and time-reversal invariance, in the $6{}_{}{}^2{}_{}{}^{}P_{\frac{1}{2}}^{}{}_{}{}^{}$ ground state of thallium. The motional magnetic field effect ($\overrightarrow{\mathrm{v}}\times \frac{\overrightarrow{\mathrm{E}}}{c}$) was accounted for by comparison experiments between Tl and Na and K. The electric dipole moment of the thallium atom is $D_{\mathrm{Tl}}=\left[\right(1.3\mathrm{}\pm 2.4)\times {10}^{-21\mathrm{}} \mathrm{cm}]e$, where the error is the standard deviation.