Sunlight-Induced Electron Ejection in Natural Waters

摘要-0099027尽管地球化学家知道，涉及溶解有色有机物（CDOM）的阳光诱导的光化学反应在天然沃茨中无处不在，但观测困难决定了对潜在反应机制的详细研究主要局限于实验室。 两种主要的实验室技术--激光闪光光解（LFP）和稳态探针（SS-P）用于引发光解，这意味着诸如CDOM的反应 + hn @ CDOM+ + 其中hn表示撞击在CDOM分子结构中的反应位点上的光子，并且eaq是因此喷射到溶液中的水合电子。 然而，研究人员一直感到困惑的是，LFP在水合电子产生方面明显比SS-P更有效。 LFP是光化学研究的重要工具，因此理解这种差异很重要。在这个项目中，来自伍兹霍尔海洋研究所、布兰迪斯大学和马里兰州大学的研究人员联合收割机通过比较淡水和河口沃茨样本的LFP和SS-P数据，重新评估了关键反应（上图）。 比较研究将使用具有良好表征的光化学性质的化合物进行校准，然后重点将转移到河口和陆地CDOM组分的详细比较研究。 如有可能，还将对未经处理的水样进行检查。

ABSTRACTOCE-0099027Although geochemists know that sunlight-induced photochemical reactions involving dissolved colored organic matter (CDOM) are ubiquitous in natural waters everywhere, observational difficulties have dictated that the detailed study of the underlying reaction mechanisms has been largely confined to the laboratory. The two principal laboratory techniques -- laser flash photolysis (LFP) and steady-state probes (SS-P) used to trigger photolysis imply reactions such asCDOM + hn @ CDOM+ + eaq-where hn represents a photon impinging upon a reactive site in the CDOM molecular structure, and eaq- is a hydrated electron ejected into solution as a consequence. However, investigators have been puzzled that LFP is significantly more efficient that SS-P in hydrated electron production. LFP is an important tool for photochemical research, so it is important to understand the discrepancy.In this project, researchers at the Woods Hole Oceanographic Institution, Brandeis University, and the University of Maryland combine efforts to re-evaluate the key reaction (above) by comparing LFP and SS-P data for samples from fresh and estuarine waters. The comparative studies would be calibrated using compounds with well-characterized photochemical properties, The focus would then shift to detailed comparative studies of estuarine and terrestrial CDOM fractions. If possible, unprocessed water samples would also be examined.