Heterogeneous Chemical Processes of Importance in the Stratosphere

小行星9322740 拟议研究的目的是增进对平流层中氯活化过程的了解。 这些过程涉及极地平流层云粒子和液态硫酸气溶胶上发生的化学反应。 必须详细了解这些多相反应的机制，以便对今后的臭氧消耗作出可靠的预测，特别是在北方高纬度地区。 一些拟议的实验旨在探讨HCl相互作用的各个方面（盐酸）蒸气与冰表面：它们包括通过监测其与DCl的同位素交换来测试HCl的溶剂化作用;调查表面形态的影响;探索在非常低的HCl分压下的吸收程度;等的结果应有助于区分各种HCl的吸收机制，提出到目前为止，即物理吸附与形成的液体状层的冰表面。 其他拟议的实验包括测量的反应概率的氯活化过程中的液体H2SO 4/（硫酸）HNO 3/（硝酸）HCl/H2O（水蒸气）的解决方案的组合物，如那些预测的气溶胶粒子在高纬度平流层。 这些实验的结果可能是非常重要的解释异常高水平的ClO（一氧化氯）自由基在平流层下部的一些空气中观察到的。

9322740 Molina The objective of the proposed research is to improve the understanding of the processes responsible for chlorine activation in the stratosphere. These processes involve chemical reactions occurring on polar stratospheric cloud particles and on liquid sulfuric acid aerosols. It is important to have a detailed knowledge of the mechanisms of these heterogeneous reactions in order to make reliable predictions of future ozone depletion, particularly at high latitudes in the Northern Hemisphere. Some of the proposed experiments are designed to probe various aspects of the interaction of HCl (hydrochloric acid) vapor with ice surfaces: They include testing the solvation of HCl by monitoring its isotopic exchange with DCl; investigating the effects of surface morphology; exploring the extent of the uptake at very low HCl partial pressures; etc. The results should help to discriminate among the various HCl uptake mechanisms proposed so far, i.e. physical adsorption vs. formation of a liquid-like layer on the ice surface. Other proposed experiments consist of measurements of the reaction probabilities for chlorine activation processes on liquid H2SO4/(sulfuric acid) HNO3/(nitric acid) HCl/H2O(water vapor) solutions with compositions such as those predicted for aerosol particles in the high-latitude stratosphere. The results of these experiments are potentially of great importance for interpreting the unusually high levels of the ClO (chlorine monoxide) radical observed in some air parcels in the lower stratosphere.