Field effects on the Rydberg product-state distribution from dielectronic recombination

The effects of state mixing by extrinsic fields in the collision region have been investigated for the dielectronic recombination process ${\mathrm{Mg}}^{+}$(3s)+e\ensuremath{\rightarrow}Mg(3p,nl)\ensuremath{\rightarrow}Mg(3s ,nl)+h\ensuremath{\nu}. By field ionization of the Rydberg atoms produced, cross sections \ensuremath{\sigma}(${n}_{f}$) have been measured. The observed large changes of \ensuremath{\sigma}(${n}_{f}$) with alteration of the extrinsic field provide the first incontrovertible experimental evidence that dielectronic recombination can be changed by external fields.