Enhanced dielectronic recombination of lithium-like Ti19+ ions in externalE x B fields

Dielectronic recombination (DR) of lithium-like Ti19+(1s(2)2s) ions via 2s --> 2p core excitations has been measured at the Heidelberg heavy ion stora ge ring TSR. We find that not only external electric fields (0 less than or equal to E less than or equal to 280 V cm(-1)) but also crossed magnetic f ields (30 less than or equal to B less than or equal to 80 mT) influence th e DR via high-n 2p(j)nl-Rydberg resonances. This result confirms our previo us finding for isoelectronic Cl14+ ions (Bartsch et al 1999 Phys. Rev. Lett . 82 3779) that experimentally established the sensitivity of DR to E x B f ields. In the present investigation the larger 2p(1/2)-2P(3/2) fine structu re splitting of Ti19+ allowed us to study separately the influence of exter nal fields via the two series of Rydberg DR resonances attached to the 2s - -> 2P(1/2) and 2s --> 2p(3/2) excitations of the Li-like core, extracting i nitial slopes and saturation fields of the enhancement. We find that for E greater than or similar to 80 V cm(-1) the field induced enhancement is abo ut 1.8 times stronger for the 2p(3/2) series than for the 2p(1/2) series.