Does normal boiling exist due to laser-pulse or ion bombardment?

We consider here the process of normal boiling as induced by laser-pulse or ion bombardment. Normal boiling (thenceforth "boiling") refers to the appearance of heterogeneously nucleated bubbles which diffuse towards the outer surface of a liquid and, if the surface is reached, may possibly escape. We will here present evidence that boiling, whether the distance scale is atomically small (5-15 nm, as for laser-pulse or ion impact on a metal in the absence of thermal diffusion) or much larger, has a prohibitive kinetic obstacle because it requires bubble diffusion. That is to say: boiling will never be a significant process for bombardment with laser pulses which are short (< 1 mu s) or with ions in general. This leaves vaporization and phase explosion as the only possible thermal-spike processes capable of expelling material from a laser-pulse or ion bombarded surface in a significant quantity. (C) 2000 American Institute of Physics. [S0021-8979(00)03006-1].