Proton transfer reaction rate constants between hydronium ion (H3O ) and volatile organic compounds

We report proton transfer reaction rate constants between the hydronium ion (H3O ) and selected atmospherically important volatile organic compounds (VOCs). The quantum chemical method was used to determine the structures of the organic species employing the density function theory-B3LYP. The ion–molecule reaction rates were determined using the average-dipole-orientation theory, along with the permanent dipole moment and polarizability of the organic species predicted from the quantum chemical calculations. The theoretical results are compared to available literature data of the permanent dipole moment, polarizability, and ion–molecule reaction rate. The newly calculated proton transfer rate constants facilitate the use of the proton transfer reaction mass spectrometry (PTR-MS) technique in applications of laboratory investigation of photochemical hydrocarbon oxidation reactions and field measurements of the abundance of VOCs. r 2004 Elsevier Ltd. All rights reserved.