摘要(英) |
Atmospheric bromine atoms come from the photolysis of dibromochloromethane (CHBr2Cl) is one importance source of the ozone depletion. The studies of the photolysis of CHBr2Cl at long ultraviolet wavelengths (>200 nm) are very limited, and the reaction mechanism is still unclear. The photolysis reaction of CHClBr2 at 266 nm was observed in a supersonic free jet expansion as well as in a slow flow cell. Nascent emission spectra were successfully acquired with an intensified charge-coupled device (ICCD) detector. In the emission spectra, several species include the CH (A2Δ), CH (B2Σ-), CH (C2Σ+), Br2 (X1Σg+), excited Br atom and the collisional product C2 were observed. The power-dependence experiments indicate that CH, excited Br atom and Br2 are likely the products of a three-photon process, a one-photon process and a two-photon process, respectively. Based upon our results and other related references, the reaction mechanisms of the 266 nm photolysis of CHClBr2 are elucidated. Moreover, in comparison with the photolysis of bromoform (CHBr3), in spite of the similar products of this photolysis, their reaction mechanisms are distinctively different. |
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