Direct Experimental Evidence for the H(2)O(+)O(2)(-) Charge Transfer Complex: Crucial Support to Atmospheric Photonucleation Theory.

Where does rain come from? The first experimental evidence for the existence of the (H(2)O(+)O(2)(-)) charge transfer complex, predicted to play a key role as a nucleation center for atmospheric vapor photonucleation (see picture), is provided by the powerful neutralization - reionization mass spectrometric technique.