Ioppolo S, Fedoseev G, Minissale M, Congiu E, Dulieu F, Linnartz H
Division of Geological and Planetary Sciences, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125, USA.
Phys Chem Chem Phys. 2014 May 14;16(18):8270-82. doi: 10.1039/c3cp54918f.
Nitrogen oxides are considered to be important astrochemical precursors of complex species and prebiotics. However, apart from the hydrogenation of solid NO that leads to the surface formation of hydroxylamine, little is known about the full solid state reaction network involving both nitrogen and oxygen. Our study is divided into two papers, hereby called Part I and Part II. In the accompanying paper, we investigate the surface reactions NO + O/O2/O3 and NO + N with a focus on the formation of NO2 ice. Here, we complement this study by measurements of the surface destruction of solid NO2, e.g., NO2 + H/O/N. Experiments are performed in two separate ultra-high vacuum setups and therefore under different experimental conditions to better constrain the experimental results. Surface reaction products are monitored by means of Fourier Transform Reflection Absorption Infrared Spectroscopy (FT-RAIRS) and Temperature Programmed Desorption (TPD) techniques using mass spectrometry. The surface destruction of solid NO2 leads to the formation of a series of nitrogen oxides such as NO, N2O, N2O3, and N2O4 as well as HNO, NH2OH, and H2O. When NO2 is mixed with an interstellar more relevant apolar (i.e., CO) ice, solid CO2 and HCOOH are also formed due to interactions between different reaction routes. The astrophysical implications of the full nitrogen and oxygen reaction network derived from Parts I and II are discussed.
氮氧化物被认为是复杂物种和益生元重要的天体化学前体。然而，除了固态NO的氢化反应会导致羟胺在表面形成外，对于涉及氮和氧的完整固态反应网络我们知之甚少。我们的研究分为两篇论文，分别称为第一部分和第二部分。在随附的论文中，我们研究了表面反应NO + O/O2/O3和NO + N，重点是NO2冰的形成。在此，我们通过测量固态NO2的表面破坏反应，如NO2 + H/O/N，对该研究进行补充。实验在两个独立的超高真空装置中进行，因此处于不同的实验条件下，以便更好地限制实验结果。使用质谱仪，通过傅里叶变换反射吸收红外光谱（FT-RAIRS）和程序升温脱附（TPD）技术监测表面反应产物。固态NO2的表面破坏反应会导致一系列氮氧化物的形成，如NO、N2O、N2O3和N2O4，以及HNO、NH2OH和H2O。当NO2与星际中更相关的非极性（即CO）冰混合时，由于不同反应路径之间的相互作用，还会形成固态CO2和HCOOH。我们讨论了从第一部分和第二部分得出的完整氮和氧反应网络对天体物理学的影响。
