Dissociation lifetimes of alkali halide dianions

LiF32- is the smallest dianion that has been predicted to be detectable in a mass spectrometer, but, so far all attempts to prove its existence have failed. In this communication we investigate the lifetimes of its vibrational states using one- and three-dimensional model Hamiltonians for the LiF32- dissociation process. Based on our findings we propose approximations to the number of states showing a long lifetime on a mass spectrometric time scale and compare the respective values for dianionic alkaline and alkaline earth fluoride systems. Further influences on the observable ion currents are briefly discussed and alternative experiments are suggested. (C) 1999 American Institute of Physics. [S0021-9606(99)01111-3].