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- ItemEvaluated kinetic and photochemical data for atmospheric chemistry: Volume I - gas phase reactions of Ox, HOx, NOx and SOx species(Katlenburg-Lindau : EGU, 2004) Atkinson, R.; Baulch, D. L.; Cox, R. A.; Crowley, J. N.; Hampson, R. F.; Hynes, R. G.; Jenkin, M. E.; Rossi, M. J.; Troe, J.This article, the first in the series, presents kinetic and photochemical data evaluated by the IUPAC Subcommittee on GasKinetic Data Evaluation for Atmospheric Chemistry. It covers the gas phase and photochemical reactions of Ox, HOx, NOx and SOx species, which were last published in 1997, and were updated on the IUPAC website in late 2001. The article consists of a summary sheet, containing the recommended kinetic parameters for the evaluated reactions, and five appendices containing the data sheets, which provide information upon which the recommendations are made.
- ItemEvaluated kinetic and photochemical data for atmospheric chemistry: Volume II - Gas phase reactions of organic species(Katlenburg-Lindau : EGU, 2006) Atkinson, R.; Baulch, D. L.; Cox, R. A.; Crowley, J. N.; Hampson, R. F.; Hynes, R. G.; Jenkin, M. E.; Rossi, M. J.; Troe, J.This article, the second in the series, presents kinetic and photochemical data evaluated by the IUPAC Sub-committee on Gas Kinetic Data Evaluation for Atmospheric Chemistry. It covers the gas phase and photochemical reactions of Organic species, which were last published in 1999, and were updated on the IUPAC website in late 2002, and subsequently during the preparation of this article. The article consists of a summary table of the recommended rate coefficients, containing the recommended kinetic parameters for the evaluated reactions, and eight appendices containing the data sheets, which provide information upon which the recommendations are made.
- ItemCompilation and evaluation of gas phase diffusion coefficients of reactive trace gases in the atmosphere: Volume 1. Inorganic compounds(Katlenburg-Lindau : EGU, 2014) Tang, M. J.; Cox, R. A.; Kalberer, M.Diffusion of gas molecules to the surface is the first step for all gas-surface reactions. Gas phase diffusion can influence and sometimes even limit the overall rates of these reactions; however, there is no database of the gas phase diffusion coefficients of atmospheric reactive trace gases. Here we compile and evaluate, for the first time, the diffusivities (pressure-independent diffusion coefficients) of atmospheric inorganic reactive trace gases reported in the literature. The measured diffusivities are then compared with estimated values using a semi-empirical method developed by Fuller et al. (1966). The diffusivities estimated using Fuller's method are typically found to be in good agreement with the measured values within ±30%, and therefore Fuller's method can be used to estimate the diffusivities of trace gases for which experimental data are not available. The two experimental methods used in the atmospheric chemistry community to measure the gas phase diffusion coefficients are also discussed. A different version of this compilation/evaluation, which will be updated when new data become available, is uploaded online (https://sites.google.com/site/mingjintang/home/diffusion).
- ItemAccurate molecular van der Waals interactions from ground-state electron density and free-atom reference data(College Park, Md. : APS, 2009) Tkatchenko, Alexandre; Scheffler, MatthiasWe present a parameter-free method for an accurate determination of long-range van der Waals interactions from mean-field electronic structure calculations. Our method relies on the summation of interatomic C6 coefficients, derived from the electron density of a molecule or solid and accurate reference data for the free atoms. The mean absolute error in the C6 coefficients is 5.5% when compared to accurate experimental values for 1225 intermolecular pairs, irrespective of the employed exchange-correlation functional. We show that the effective atomic C6 coefficients depend strongly on the bonding environment of an atom in a molecule. Finally, we analyze the van der Waals radii and the damping function in the C6R-6 correction method for density-functional theory calculations. © 2009 The American Physical Society.
- ItemRadio Frequency Electromagnetic Radiation From Streamer Collisions(Hoboken, NJ : Wiley, 2017) Luque, AlejandroWe present a full electromagnetic model of streamer propagation where the Maxwell equations are solved self-consistently together with electron transport and reactions including photoionization. We apply this model to the collision of counter-propagating streamers in gaps tens of centimeters wide and with large potential differences of hundreds of kilovolts. Our results show that streamer collisions emit electromagnetic pulses that, at atmospheric pressure, dominate the radio frequency spectrum of an extended corona in the range from about 100 MHz to a few gigahertz. We also investigate the fast penetration, after a collision, of electromagnetic fields into the streamer heads and show that these fields are capable of accelerating electrons up to about 100 keV. By substantiating the link between X-rays and high-frequency radio emissions and by describing a mechanism for the early acceleration of runaway electrons, our results support the hypothesis that streamer collisions are essential precursors of high-energy processes in electric discharges.