We have studied methods of varying the ion species generated by a lithium‐fluoride overcoated anode in a 0.5‐MV magnetically insulated ion diode. We found that cleaning the anode surface with a 13.6‐MHz rf glow discharge or illuminating the anode with a pulsed soft x‐ray, vacuum‐ultraviolet (XUV) radiation source just before the accelerator pulse significantly altered the ion species of the ion beam produced by the diode. The glow‐discharge plasma removed adsorbates (carbon, hydrogen, and oxygen) from the surface of the LiF flashover source. The ions seen were lithium and hydrogen. Unfortunately, the diode impedance with a lithium‐fluoride anode was high and the ion efficiency was low; however, XUV irradiation of the surface dramatically lowered the impedance by desorbing neutrals from the ion source via photon‐stimulated desorption. Current densities of ten times the Child–Langmuir space‐charge limit were achieved under XUV irradiation. In particular, ion currents increased by over a factor of 3 when 12 mJ/cm2of XUV radiation was used. However, with XUV irradiation the largest fraction of ions were fluorine, oxygen, carbon, and hydrogen, not lithium.