在太空中漂浮:如何处理星际冰层中CO分子之间的弱相互作用
Brian C Ferrari1, Germán Molpeceres2, Johannes Kästner3
1Leiden Institute of Chemistry, Leiden University, Leiden 2300 RA, The Netherlands.
ACS earth & space chemistry
|July 26, 2023
概括
这项研究以计算方式调查太空中的一氧化碳 (CO) 冰,揭示了CO如何与冰的尘埃粒结合的关键细节. 了解这些二氧化碳冰相互作用是形成星际介质中复杂有机分子的关键.
科学领域:
- 天体化学是天体化学.
- 计算化学计算化学
- 材料科学 材料科学 材料科学
背景情况:
- 尘埃颗粒上的星际冰对复杂分子形成至关重要.
- 一氧化碳 (CO) 冰的结构,特别是富含CO的外层,是有争议的,这对有机合成有影响.
- 需要对二氧化碳表面过程的原子洞察力来验证结构模型.
研究的目的:
- 用计算方法研究纯一氧化碳 (CO) 冰的弱相互作用和吸附.
- 为了对密度函数理论 (DFT) 方法进行基准测试,用于模拟 CO 流量.
- 为了研究CO在无形和晶体CO上的结合能.
主要方法:
- 密度函数理论 (DFT) 计算用于对CO 冰的基准方法.
- 原子模拟使用基于对电位的力场来研究CO结合能.
- 对无形和晶体CO冰结构上的结合能分布的分析.
主要成果:
- 无形CO冰上CO吸附显示了广泛的结合能 (200-1600 K),包括许多弱点 (<350 K).
- 增加集群大小和邻居数量会提高二氧化碳的平均结合能量.
- 二氧化碳的结合能量受到分散力的显著影响,因此需要分散校正的功能.
结论:
- 精确模拟CO冰的表面过程需要密度函数理论方法,包括分散校正.
- ωB97M-V 功能表现为模拟CO 冰的表面过程具有前途.
- 这项工作为了解CO冰结构及其在天体化学中的作用提供了基础的原子学数据.
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