在极地冰中减少化的光降解
Javier Carmona-García1,2,3, Alfonso Saiz-Lopez2, Anoop S Mahajan4
1Institut de Ciència Molecular, Universitat de València, València 46980, Spain.
概括
极地地区的污染因大气中耗尽事件 (AMDEs) 而减少. 冰中的光化学有效地将再发射回大气中,影响循环.
科学领域:
- 环境化学环境化学
- 大气化学 大气化学
- 量子化学 是一个量子化学.
背景情况:
- 极地地区对污染敏感.
- 大气中的耗事件 (AMDEs) 通过氧化将元素 (Hg(0)) 转化为氧化 (Hg(II)).
- Hg(II) 沉积在雪和海冰上,其中很大一部分通过光化学过程重新排放.
研究的目的:
- 为了阐明驱动极地冰的再排放的基本光化学.
- 与气相相比,研究水银化物光还原在冰中的效率.
主要方法:
- 采用了多配置的量子化学计算.
- 分析了水分子对化几何和冰中的电子结构的影响.
- 动力建模用于估计再排放率.
主要成果:
- 对HgBr2,HgBr3-和HgBr42-的光降解在冰中比在气相中更有效.
- 冰中的水分子在热层波长 (λ>290 nm) 上增强了化的吸收强度.
- 动力建模表明,30-60%的沉积可以从冰中重新排放.
结论:
- 已经确定了一种光还原机制,涉及太阳光诱导的水银化物在冰上的激发状态化学.
- 这种冰大气循环机制对极地环境至关重要.
- 当前的大气模型需要将这种光化学纳入,以准确评估循环.
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