High-resolution laser spectroscopy of aluminium, gallium and thallium

Applying the techniques of resonant and off-resonant Doppler-free 2-photon laser spectroscopy, we have studied a number of transitions in the group IIIa elements Al, Ga and Tl with the thermionic diode. In order to check the accuracy of the experimental set-up and the spectroscopic method applied, the hfs of the intermediate state 3d2D3/2,5/2 of 27Al has been determined from the spectra of the 3p2PJ-3d2DJ-nf2FJ or -np2PJ transitions and compared with more precise values by other authors from atomic beam magnetic resonance measurements. From 4p2P1/2-nf2FJ and 4p2PJ-4d2DJ-nf2FJ or -np2PJ transitions in 69,71Ga, we have deduced the hfs and the residual level isotope shifts (RLIS) of the intermediate states (4d2D3/2,5/2) and the RLIS of the 4p2P1/2,3/2 ground states. In Tl, we have measured the 6p2P1/2-nf2F5/2 (n=6-9) and -10p2p3/2 lines. From the experimental results we have determined the residual level isotope shift (205,203Tl) of the 6p2P1/2 state and the hfs of the 10p2P3/2 level. (orig.)