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 f ailed. In this communication we investigate the lifetimes of its vibrationa l states using one- and three-dimensional model Hamiltonians for the LiF32- dissociation process. Based on our findings we propose approximations to t he number of states showing a long lifetime on a mass spectrometric time sc ale and compare the respective values for dianionic alkaline and alkaline e arth fluoride systems. Further influences on the observable ion currents ar e briefly discussed and alternative experiments are suggested. (C) 1999 Ame rican Institute of Physics. [S0021-9606(99)01111-3].