Speaker
Description
Sea salt aerosols are among the most abundant natural aerosols and play a significant role for the climate. They mainly consist of sodium chloride, which is involved in chemical reactions in the atmosphere with atmospherically relevant trace gases. Such reactions are simulated in our experiments.
We use electrospray ionization (ESI) to produce gas-phase sodium chloride cluster ions. Atmospherically relevant acids, e.g. formic and pyruvic acid, are introduced as reaction gas into the ICR cell of a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) and reaction kinetics are recorded. We observe a sequential acid uptake by both anions and cations, accompanied by HCl release. We find a reactivity dependence on the proton affinity of the conjugate base. Interestingly, magic cluster sizes show a reduced reactivity for each acid used in our experiments. Detailed quantum chemical calculations reveal how a weak organig acid is able to displace HCl, known to be a strong acid.
