Experimental results on the processing of NH3:CO ice mixtures of astrophysical relevance by energetic (538 MeV ⁶⁴Ni^{24 +}) projectiles are presented. NH₃ and CO are two molecules relatively common in interstellar medium and solar system; they may be precursors of amino acids. ⁶⁴Ni ions may be considered as representative of heavy cosmic ray analogues. Laboratory data were collected using mid-infrared Fourier transform (FTIR) spectroscopy and revealed the formation of ammonium cation (NH|$_4^+$|⁠), cyanate (OCN⁻), molecular nitrogen (N₂), and CO₂. Tentative assignments of carbamic acid (NH₂COOH), formate ion (HCOO⁻), zwitterionic glycine (NH|$_3^+$|CH₂COO⁻), and ammonium carbamate (NH|$_4^+$|NH₂COO⁻) are proposed. Despite the confirmation on the synthesis of several complex species bearing C, H, O, and N atoms, no N-O bearing species was detected. Moreover, parameters relevant for computational astrophysics, such as destruction and formation cross sections, are determined for the precursor and the main detected species. Those values scale with the electronic stopping power (S_e) roughly as σ ∼ a S|$_e^n$|⁠, where n ∼ 3/2. The power law is helpful for predicting the CO and NH₃ dissociation and CO₂ formation cross-sections for other ions and energies; these predictions allow estimating the effects of the entire Cosmic ray radiation field.

中文翻译：

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NH ₃：CO冰混合物的辐射分解-对太阳系和星际冰的影响

提出了利用高能（538 MeV ⁶⁴ Ni ^{24 +}）弹丸处理天体相关的NH3：CO冰混合物的实验结果。NH ₃和CO是星际介质和太阳系中相对常见的两个分子。它们可能是氨基酸的前体。⁶⁴ Ni离子可被视为重宇宙射线类似物的代表。使用中红外傅里叶变换光谱（FTIR），收集和显示阳离子铵的形成实验室数据（NH | $ _4 ^ + $ |⁠），氰酸酯（OCN ^- ），分子氮（N ₂）和CO ₂。氨基甲酸（NH ₂COOH），甲酸根离子（HCOO ^- ），两性离子型甘氨酸（NH | $ _3 ^ + $ | CH ₂ COO ^- ），和氨基甲酸铵（NH | $ _4 ^ + $ | NH ₂ COO ^- ）提出。尽管已经证实了几种带有C，H，O和N原子的复杂物种的合成，但未检测到带有NO的物种。此外，针对前体和主要探测物种确定了与计算天体物理学相关的参数，例如破坏和地层横截面。这些值与电子制动力（S _e）大致成比例σσa | S | $ _e ^ n $ |⁠，其中n约3/2。幂定律有助于预测其他离子和能量的CO和NH ₃离解和CO ₂形成截面。这些预测可以估算整个宇宙射线辐射场的影响。