Hyperfine structure and isotopic shift of the n 2PJ levels (n=7-10) of 203,205Tl measured by Doppler-free two-photon spectroscopy.

Abstract

Using Doppler-free two-photon absorption spectroscopy, we have measured hyperfine splitting constants as well as isotopic level shifts of the 6${s}^{2}$np $^{2}P_{1/2}$,3/2 states (n=7\char21{}10) in $^{203}\mathrm{Tl}$ and $^{205}\mathrm{Tl}$. Calculations for hyperfine constants and electron density at the nucleus have been performed by the Dirac-Fock method. The experimental results are compared with these calculations as well as with the predictions of the semiempirical theory.