Ultra-low-temperature reactions of C and Si atoms inside superfluid helium nanodroplets

超流氦纳米液滴内C和Si原子的超低温反应

基本信息

批准号：
316660419
负责人：
Dr. Sergiy Krasnokutskiy
金额：
--
依托单位：
Laboratory Astrophysics and Cluster Physics Group
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/316660419?language=en
关键词：
Ultra low temperature reactions Si

项目摘要

Carbon and silicon are the main components of refractory dust grains in astrophysical environments. There are strong arguments in favor of the fact that the dust formation occurs directly in the cold regions of the interstellar medium (ISM). This project is devoted to the study of chemical reactions involving C and Si atoms, which could be relevant to the formation of refractory dust in the ISM. The reactions will be studied at ultra-low-temperature (T = 0.37 K) in superfluid helium nanodroplets. The reactions proceeding at this temperature have no energy barrier and, therefore, they are expected to be fast in the entire low-temperature range encountered in the ISM. At the beginning of the project, we will improve the accuracy of the calorimetric technique to measure more precisely the reaction energies. During the later stages of the project, the developed technique, in combination with quantum chemical calculations, will be used for the determination of the active reaction channels. The reactions of C and Si atoms with molecules modeling the surface of astrophysical dust grains will be studied. Diamondoid molecules will simulate the hydrogenated diamond surface while large polycyclic aromatic hydrocarbon (PAH) molecules are close analogues of the graphite surface and small silicate clusters mimic the surface of silicate grains. The observation of strong chemical bonds in our experiments will demonstrate high binding energies between the corresponding atoms and surfaces. Apart from studying the reactivity of individual species, we will also focus on the condensation of carbon atoms inside helium droplets. Large helium droplets containing millions or even billions of He atoms will be used to pick up gas-phase carbon atoms and condense them. The formed carbon nanoparticles and possibly nanowires will be deposited on appropriate substrates and analyzed by high-resolution transmission electron microscopy (HRTEM), UV/VIS and IR absorption spectroscopy, Raman spectroscopy, and atomic force microscopy (AFM). These studies will reveal the preferred allotropic form of the carbonaceous material produced by low-temperature condensation of carbon atoms. The spectral properties of the produced carbon nanoparticles will be studied and compared with the astrophysical observations. Moreover, the properties of carbon nanowires, which are expected to be formed in the largest helium droplets, should be particularly interesting for applications in nanoelectronics.

碳和硅是天体物理环境中难治性粉尘颗粒的主要组成部分。有强有力的论点，即尘埃形成直接发生在星际介质（ISM）的冷区域中。该项目致力于研究涉及C和SI原子的化学反应，这可能与ISM中难治性灰尘形成有关。这些反应将在超高温度（t = 0.37 K）中研究，在超流体氦纳米光中。在此温度下进行的反应没有能屏障，因此，预计它们在ISM中遇到的整个低温范围内会很快。在项目开始时，我们将提高量热技术的准确性，以更精确地测量反应能。在项目的后期阶段，开发的技术将与量子化学计算结合使用，用于测定活动反应通道。将研究C和Si原子与分子对天体物理粉尘晶粒表面进行建模的反应。钻石分子将模拟氢化钻石表面，而大型多环芳烃（PAH）分子是石墨表面的紧密类似物，而小硅酸盐簇模仿硅酸盐晶粒的表面。在我们的实验中，对强化学键的观察将证明相应的原子和表面之间的高结合能。除了研究单个物种的反应性外，我们还将重点关注氦液滴内碳原子的凝结。包含数百万甚至数十亿原子的大型氦液滴将用于拾取气相碳原子并凝结。形成的碳纳米颗粒以及可能的纳米线将沉积在适当的底物上，并通过高分辨率透射电子显微镜（HRTEM），UV/VIS和IR吸收光谱，拉曼光谱镜检查，原子力显微镜（AFM）进行分析。这些研究将揭示由碳原子低温凝结产生的碳质材料的首选同类异形形式。将研究产生的碳纳米颗粒的光谱特性，并将其与天体物理观测值进行比较。此外，预计将在最大的氦液滴中形成的碳纳米线的性能对于纳米电子中的应用特别有趣。

项目成果

期刊论文数量（4）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Formation of a long-lived cyclic isomer of ethylenedione.

乙二酮长寿命环状异构体的形成

DOI：
10.1039/c9cp01616c
发表时间：
2019
期刊：
Physical chemistry chemical physics : PCCP
影响因子：
0
作者：
S. A. Krasnokutski;O. Tkachenko;C. Jäger;Th. Henning
通讯作者：
Th. Henning

Fullerene Oligomers and Polymers as Carriers of Unidentified IR Emission Bands

富勒烯低聚物和聚合物作为未知红外发射带的载体

DOI：
10.3847/1538-4357/ab095d
发表时间：
2019
期刊：
The Astrophysical Journal
影响因子：
0
作者：
S. A. Krasnokutski;M. Gruenewald;C. Jäger;F. Otto;R. Forker;T. Fritz;Th Henning
通讯作者：
Th Henning

Experimental characterization of the energetics of low-temperature surface reactions

低温表面反应能量的实验表征