Abstract

With the aim to determine higher order atomic effects in the hyperfinestructure (hfs) or isotope shift (IS) for lanthanide elements various high resolution experimental techniques were applied, e.g. Doppler-free two-photon spectroscopy,^[1] laserinduced fluorescence spectroscopy^[2] or intermodulated opto-galvanic spectroscopy.^[3] The first two methodes are generally restricted to excitations from low-energy levels while the latter is often limited in its spectral resolution due to velocity-changing-collision effects. We introduced the Sub-Doppler method of saturation absorption spectroscopy in a vapor of a heavy element produced and excited with discharge currents up to 1 A in a see-through hollow-cathode or in a heat-pipe. The self-developed hollow-cathode discharge chamber with a closed water-cooling system pocesses a cylindrical cathode made out of the investigated element. At present we investigate the highly refractory elements Gd, Er, and Re in a hollow-cathode and Eu in a heat-pipe, for which particle densities up to 10¹⁶ cm⁻³ are easily achievable.

© 1992 IQEC