碳酸的矩阵隔离研究 - - 在β-多形态上方的蒸汽相
Jürgen Bernard1, Roland G Huber, Klaus R Liedl
1Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck, Austria.
Journal of the American Chemical Society
|May 2, 2013
概括
研究人员通过升华和矩阵分离成功分离并研究了碳酸 (H2CO3) 的β多态. 这一发现对于理解天体物理环境中的碳酸化学是至关重要的.
科学领域:
- 天体化学是天体化学.
- 固态化学 固态化学
- 频谱学是一种光谱学.
背景情况:
- 碳酸的两个多态 (α-和β-H2CO3) 之前被分离为晶膜,并使用红外和拉曼光谱学进行研究.
- 使用X射线衍射来确定这些多态的晶体结构一直是具有挑战性的.
- 之前的研究表明β-H2CO3在升华后分解,与α-H2CO3.3不同.
研究的目的:
- 为了研究碳酸β多态体的升华和再冷凝特性.
- 在高贵气体矩阵中分析β-H2CO3的分子结构和对象.
- 评估β-H2CO3稳定性对天体物理环境的影响.
主要方法:
- 升华β-H2CO3并将蒸汽相捕获在贵气矩阵中.
- 使用富里埃变换红外光谱法 (FTIR) 分析被困的分子.
- 将FTIR光谱与α-H2CO3.3的光谱进行比较.
主要成果:
- 在矩阵中成功分离未分解的碳酸,并在删除矩阵后实现再冷凝,证明β-H2CO3.3的升华和再冷凝周期.
- 在FTIR的光谱分配中,发现了两个不同的碳酸单体对应体 (C(2v) 和C(s)).
- 没有发现中心对称碳酸二聚体 (C(2h)) 的证据,这表明单聚体在250 K时对β-H2CO3.3具有热优势.
结论:
- 在升华和再冷凝周期期间β-H2CO3的稳定性是天体化学的一个重要发现.
- 在β-多态体中存在单体碳酸合物的存在与先前对α-多态体的发现形成鲜明对比.
- 在β-H2CO3.3的升温温度下,热因素可能有利于单体碳酸.
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