Molecular oxygen, nitrogen, and ozone have been detected in the Solar System. They are also expected to be present in ice-grain mantles within star-forming regions. Laboratory experiments that simulate energetic processing (ions, photons, and electrons) of ices are essential for interpreting and directing future astronomical observations. We provide VUV photoabsorption spectroscopic data of energetically processed nitrogen- and oxygen-rich ices that will help to identify absorption bands and/or spectral slopes observed on icy objects in the Solar System and on ice-grain mantles of the interstellar medium. We present VUV photoabsorption spectra of frozen O2 and N2, a 1:1 mixture of both, and a new systematic set of pure and mixed nitrogen oxide ices. Spectra were obtained at 22 K before and after 1 keV electron bombardment of the ice sample. Ices were then annealed to higher temperatures to study their thermal evolution. In addition, Fourier-transform infrared spectroscopy was used as a secondary probe of molecular synthesis to better identify the physical and chemical processes at play. Our VUV data show that ozone and the azide radical (N3) are observed in our experiments after electron irradiation of pure O2 and N2 ices, respectively. Energetic processing of an O2:N2 = 1:1 ice mixture leads to the formation of ozone along with a series of nitrogen oxides. The electron irradiation of solid nitrogen oxides, pure and in mixtures, induces the formation of new species such as O2, N2 , and other nitrogen oxides not present in the initial ice. Results are discussed here in light of their relevance to various astrophysical environments. Finally, we show that VUV spectra of solid NO2 and water can reproduce the observational VUV profile of the cold surface of Enceladus, Dione, and Rhea, strongly suggesting the presence of nitrogen oxides on the surface of the icy Saturn moons.
Vacuum ultraviolet photoabsorption spectroscopy of space-related ices: Formation and destruction of solid carbonic acid upon 1~keV electron irradiation
碳酸（H2 CO 3）是一种与天体生物学有关的弱酸，迄今为止，在太空中尚未发现。实验工作表明，β-多晶型的H2 CO 3的形式在空间相关的条件下，通过高能（紫外光子，电子和宇宙射线）处理的CO2和H2O丰富的冰。我们提出了一套系统的真空紫外光吸收光谱的纯和混合CO2和H2O冰暴露于1 keV的电子在20和80 K模拟不同的星际和太阳系环境。然后将冰退火以获得纯H2 CO 3层，其进一步暴露于20和80 K下的1 keV电子以监测其破坏途径。傅里叶变换红外（FT-IR）光谱被用作二次探针提供补充信息的物理化学变化内的冰。我们的实验室工作表明，固体H2 CO 3，CO和O3的形成后，高能处理的CO2：H2O冰混合物是温度依赖的范围内20和80 K之间。通过在200和225 K下对H2 CO 3冰进行退火，首次在真空紫外光谱范围内研究了冰的非晶-晶相变。我们在139和200 nm处检测到两个光吸收带，并将它们分别归属于β-H2 CO 3和γ-H2 CO 3。我们提出了真空紫外光谱的电子辐照退火H2 CO 3冰在不同温度下导致其分解成CO2，H2O，和CO冰。实验室的结果相比，卡西尼紫外成像光谱仪观测的70-90 K的土星卫星土卫二，土卫四，土卫五和土卫五的冰表面。
Formation of nitriles and isonitriles by the heavy-ion irradiation of propionitrile in N2-rich astrophysical ices
Centre de Recherche sur les Ions, les Matériaux et la Photonique (CIMAP), Université Caen Normandie（离子、材料与光子研究中心，诺曼底大学）；Departamento de Física, Centro Federal de Educação Tecnológica Celso Suckow da Fonseca (CEFET/RJ)（物理系，塞尔索·苏克瓦·达丰塞卡联邦技术学院）
Water enhances the formation of refractory sulfur in interstellar ices
Centro de Astrobiología (CAB), INTA-CSIC（西班牙国家航空航天技术研究所-西班牙国家科学研究委员会天体生物学中心）；Departamento de Física de la Tierra y Astrofísica, Facultad de Ciencias Físicas, Universidad Complutense de Madrid（马德里康普顿斯大学物理科学学院地球与天体物理学系）；Instituto de Química Física Blas Cabrera (CSIC)（西班牙国家科学研究委员会布拉斯·卡布雷拉物理化学研究所）；Department of Physics, National Central University（中原大学物理系）
