Formulation of the cosmic ray-driven electron-induced reaction mechanism for quantitative understanding of global ozone depletion

Electron-triggered processes in halogenated carboxylates: dissociation pathways in CF3COCl and its clusters

Trifluoroacetyl chloride, CF3COCl, is produced in the Earth's atmosphere by photooxidative degradation of hydrochlorofluorocarbons, and represents a potential source of highly reactive halogen radicals. Despite considerable insight into photochemistry of CF3COCl, its reactivity towards electrons has not been addressed so far. We investigate the electron ionization and attachment in isolated CF3COCl molecules and (CF3COCl)N, max. N ≥ 10, clusters using a molecular beam experiment in combination with quantum chemical calculations. The ionization of the molecule at 70 eV electron energy leads to strong fragmentation: weakening of the C-C bond yields the CF3+ and COCl+ ions, while the fission of the C-Cl bond produces the major CF3CO+ fragment ion. The cluster spectra are dominated by Mn·COCl+ and Mn·CF3CO+ ions (M = CF3COCl). The electron attachment at energies between 1.5 and 11 eV also leads to the dissociation of the molecule breaking either the C-Cl bond at low energies below 3 eV yielding mainly Cl- ions, or dissociating the C-C bond at higher energies above 4 eV leading mainly to CF3- ions. In the clusters, the intact Mn- ions are stabilized after electron attachment at low energies with contribution of Mn·Cl- fragment ions. At higher energies, the Mn·Cl- fragments dominate the spectra, and C-C bond dissociation occurs as well yielding Mn·CF3-. Interestingly, Mn·Cl2- ions appear in the spectra at higher energies. We briefly discuss possible atmospheric implications.

Critical Review on Radiative Forcing and Climate Models for Global Climate Change since 1970

This review identifies a critical problem in the fundamental physics of current climate models. The large greenhouse effect of rising CO2 assumed in climate models is assessed by six key observations from ground- and satellite-based measurements. This assessment is enhanced by statistical analyses and model calculations of global or regional mean surface temperature changes by conventional climate models and by a conceptual quantum physical model of global warming due to halogen-containing greenhouse gases (halo-GHGs). The postulated large radiative forcing of CO2 in conventional climate models does not agree with satellite observations. Satellite-observed warming pattern resembles closely the atmospheric distribution of chlorofluorocarbons (CFCs). This review helps understand recent remarkable observations of reversals from cooling to warming in the lower stratosphere over most continents and in the upper stratosphere at high latitudes, surface warming cessations in the Antarctic, North America, UK, and Northern-Hemisphere (NH) extratropics, and the stabilization in NH or North America snow cover, since the turn of the century. The complementary observation of surface temperature changes in 3 representative regions (Central England, the Antarctic, and the Arctic) sheds new light on the primary mechanism of global warming. These observations agree well with not CO2-based climate models but the CFC-warming quantum physical model. The latter offers parameter-free analytical calculations of surface temperature changes, exhibiting remarkable agreement with observations. These observations overwhelmingly support an emerging picture that halo-GHGs made the dominant contribution to global warming in the late 20th century and that a gradual reversal in warming has occurred since ~2005 due to the phasing out of halo-GHGs. Advances and insights from this review may help humans make rational policies to reverse the past warming and maintain a healthy economy and ecosystem.