Hyperfine structure and isotopic shift of the nPJ2levels (n=7–10) of203,205Tl 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 6s2np P1/22,3/2 states (n=7–10) in Tl203 and Tl205. 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.