Atmospheric Chemistry and Physics Discussions

Interactive comment on “Chemical ionization mass spectrometry (CIMS) may not measure all gas-phase sulfuric acid if base molecules are present ” by T. Kurtén et al. Anonymous Referee #2 Received and published: 10 February 2011 Kurten et al. present a theoretical study on the ability of CIMS systems designed for the measurement of gaseous sulfuric acid in the atmosphere to also measure sulfuric acid in neutral clusters with other molecules. They use quantum chemical approximations to derive cluster binding energies between various molecules and between molecule (-clusters) and ions. By further using mass balances and chemical equilibrium consid-erations they try to characterize the charging probability of various neutral clusters by nitrate-nitric acid clusters in CIMS. As a result of this study, certain amine containing clusters and some of the ammonia containing clusters may not be charged quantita-tively by nitrate based ionization, and the efficiency of charging further depends on the experimental conditions of the CIMS system