Some speculations on the mechanisms of photochemical vapor generation

Possible mechanisms are advanced to account for a number of observations/phenomena associated with the production of volatile metal species arising from photochemical vapor generation in acetic and formic acid media. These systems include mercury, iodine, selenium, iron and nickel as test cases which generate cold vapor, hydrides, methylated and carbonylated species. A model, based on the photochemical generation of free radicals involving ligand to metal charge transfer reductions and oxidations, is consistent with the majority of experimental data, including the identity of the resultant species and the impact of external parameters. This mechanistic framework will hopefully serve to enhance understanding of the technique so as to elicit enhanced performance through development of improved hardware and minimization/control of interferences.