Laboratory Studies of Tropospheric Sulfur Chemistry

小行星9412237 这个为期四年的计划将涉及持续的研究，旨在阐明控制硫化合物的大气氧化的动力学和反应机制，特别强调二甲硫醚（CH 3\SCH 3，DMS）的氧化途径。 该计划的目标是确定还原硫化合物转化为相对稳定的S（IV）和S（VI）以及诸如二氧化硫（SO2）、硫酸（H2SO 4）、亚砜、砜和磺酸的产物的速率和机制。 直接的，“真实的时间”的活性中间体和稳定的最终产品的观察是强调，因为只有通过这样的观察可以得到一个独特的解释结果。 这项研究将大大有助于我们了解全球硫循环，从而促进准确评估生物和人为硫对气候变化（或调节），能见度降低和酸雨等问题的贡献。 具体的实验研究将集中于DMS、DMS加合物、DMSO（CH 3SOCH 3）、羰基硫（OCS）和SO 3（H2）加合物。 实验方法将涉及耦合自由基产生的激光闪光光解与一些时间分辨的检测技术，包括脉冲激光诱导荧光，原子共振荧光，紫外-可见吸收使用非相干和激光光源，红外可调谐二极管激光吸收，光电离质谱，共振增强多光子电离质谱。 在这些机理研究中，在10- 7-10-3 s时间尺度上获得时间分辨数据的能力对于定义导致产物形成的详细反应序列至关重要。 当然，研究人员将跟上其他实验室的进展和对流层化学领域的新发展，并可能稍微改变他们的子任务，以适应新确定的研究需要。 ***

9412237 Wine This four year program will involve continuing research aimed at elucidating the kinetics and reaction mechanisms which control the atmospheric oxidation of sulfur compounds, with particular emphasis oxidation pathways for dimethylsulfide (CH3 \SCH3, DMS). The goals of the program is the definitive determination of the rates and mechanisms for conversion of reduced sulfur compounds to relatively stable S(IV and S(VI) and products such as sulfur dioxide (SO2), sulfuric acid (H2S04), sulfoxides, sulfones and sulfonic acids. Direct, "real time" observations of reactive intermediates and stable end products is emphasized because only through such observations can results with a unique interpretation be obtained. The research will contribute significantly to our understanding of the global sulfur cycle, thus facilitating accurate assessment of the contribution of both biogenic and anthropogenic sulfur to such problems as climate modification (or regulation), visibility reduction, and acid precipitation. Specific experimental investigations will focus on DMS, DMS adducts, DMSO (CH3SOCH3), carbonyl sulfide (OCS), and S03 H2) adducts. The experimental methodology will involve coupling radical generation by laser flash photolysis with a number of time-resolved detection techniques including pulsed laser induced fluorescence, atomic resonance fluorescence, UV-visible absorption using both incoherent and laser light sources, infrared tunable diode laser absorption, photoionization mass spectrometry, and resonance enhanced multiphoton ionization mass spectrometry. In these mechanistic studies, th ability to obtain time-resolved data on 10- 7-10-3 s time scales is critical to defining the detailed reaction sequences leading to product formation. The investigators will, of course, keep abreast of progress in other laboratories and new developments in the area of tropospheric chemistry, and may alter their sub-tasks somewhat to accomm odate newly identified research needs. ***