Sanz-Novo M, Belloche A, Alonso J L, Kolesniková L, Garrod R T, Mata S, Müller H S P, Menten K M, Gong Y
Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopía y Bioespectroscopía, Parque Científico UVa, Unidad Asociada CSIC, E-47011 Valladolid, Spain.
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany.
Astron Astrophys. 2020 Jul 23;639. doi: 10.1051/0004-6361/202038149. eCollection 2020 Jul.
Glycolamide is a glycine isomer and also one of the simplest derivatives of acetamide (e.g., one hydrogen atom is replaced with a hydroxyl group), which is a known interstellar molecule.
In this context, the aim of our work is to provide direct experimental frequencies of the ground vibrational state of glycolamide in the centimeter-, millimeter- and submillimeter-wavelength regions in order to enable its identification in the interstellar medium.
We employed a battery of state-of-the-art rotational spectroscopic techniques in the frequency and time domain to measure the frequencies of glycolamide. We used the spectral line survey named Exploring Molecular Complexity with ALMA (EMoCA), which was performed toward the star forming region Sgr B2(N) with ALMA to search for glycolamide in space. We also searched for glycolamide toward Sgr B2(N) with the Effelsberg radio telescope. The astronomical spectra were analyzed under the local thermodynamic equilibrium approximation. We used the gas-grain chemical kinetics model MAGICKAL to interpret the results of the astronomical observations.
About 1500 transitions have been newly assigned up to 460 GHz to the most stable conformer, and a precise set of spectroscopic constants was determined. Spectral features of glycolamide were then searched for in the prominent hot molecular core Sgr B2(N2). We report the nondetection of glycolamide toward this source with an abundance at least six and five times lower than that of acetamide and glycolaldehyde, respectively. Our astrochemical model suggests that glycolamide may be present in this source at a level just below the upper limit, which was derived from the EMoCA survey. We could also not detect the molecule in the region's extended molecular envelope, which was probed with the Effelsberg telescope. We find an upper limit to its column density that is similar to the column densities obtained earlier for acetamide and glycolaldehyde with the Green Bank Telescope.
乙醇酰胺是甘氨酸的异构体，也是乙酰胺最简单的衍生物之一（例如，一个氢原子被羟基取代），乙酰胺是一种已知的星际分子。
在此背景下，我们工作的目的是提供乙醇酰胺基态振动在厘米、毫米和亚毫米波长区域的直接实验频率，以便能够在星际介质中识别它。
我们采用了一系列频率和时域的先进旋转光谱技术来测量乙醇酰胺的频率。我们使用了名为“利用阿塔卡马大型毫米波阵列探索分子复杂性”（EMoCA）的光谱线调查，该调查是用阿塔卡马大型毫米波阵列对恒星形成区域人马座B2（N）进行的，以在太空中搜索乙醇酰胺。我们还用埃费尔斯贝格射电望远镜在人马座B2（N）方向搜索乙醇酰胺。在局部热力学平衡近似下分析了天文光谱。我们使用气粒化学动力学模型MAGICKAL来解释天文观测结果。
已为最稳定构象体新指定了高达460吉赫兹的约1500个跃迁，并确定了一组精确的光谱常数。然后在突出的热分子核人马座B2（N2）中搜索乙醇酰胺的光谱特征。我们报告在该源中未检测到乙醇酰胺，其丰度分别至少比乙酰胺和乙醇醛低六倍和五倍。我们的天体化学模型表明，乙醇酰胺在该源中的存在水平可能略低于EMoCA调查得出的上限。我们在埃费尔斯贝格望远镜探测的该区域扩展分子包层中也未检测到该分子。我们发现其柱密度的上限与早期用绿岸望远镜获得的乙酰胺和乙醇醛的柱密度相似。
