Kolesniková L, Alonso E R, Tercero B, Cernicharo J, Alonso J L
Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, E-47011 Valladolid, Spain.
Observatorio Astronómico Nacional (OAN-IGN). Calle Alfonso XII, 3, E-28014 Madrid, Spain.
Astron Astrophys. 2018 Aug;616. doi: 10.1051/0004-6361/201833223. Epub 2018 Sep 7.
Relatively high abundances of methyl isocyanate (CHNCO), a methyl derivative of isocyanic acid (HNCO), found in the Orion KL and Sgr B2 molecular clouds suggest that its ethyl derivative, ethyl isocyanate (CHCHNCO), may also be present.
The aim of this work is to provide accurate experimental frequencies of ethyl isocyanate in its ground and excited vibrational states in the millimeter wave region to support searches for it in the interstellar medium.
The rotational spectrum of ethyl isocyanate was recorded at room temperature from 80 to 340 GHz using the millimeter wave spectrometer in Valladolid. Assigned rotational transitions were analyzed using the -reduced semirigid-rotor Hamiltonian.
More than 1100 distinct frequency lines were analyzed for the ground vibrational state of the conformer as well as for three vibrational satellites corresponding to successive excitation of the lowest-energy C-N torsional mode. Newly determined rotational and centrifugal distortion constants were used for searches of spectral features of ethyl isocyanate in Orion KL and Sgr B2 clouds. Upper limits to CHCHNCO in these high-mass star-forming regions were obtained.
在猎户座KL和人马座B2分子云中发现了相对高丰度的异氰酸甲酯（CHNCO），它是异氰酸（HNCO）的甲基衍生物，这表明其乙基衍生物异氰酸乙酯（CHCHNCO）可能也存在。
这项工作的目的是提供毫米波区域内异氰酸乙酯基态和激发振动态的精确实验频率，以支持在星际介质中对其进行搜寻。
使用巴利亚多利德的毫米波光谱仪在室温下于80至340GHz记录了异氰酸乙酯的转动光谱。使用 - 简化半刚性转子哈密顿量对指定的转动跃迁进行了分析。
对 构象异构体的基态以及对应于最低能量C - N扭转模式连续激发的三个振动卫星的1100多条不同频率线进行了分析。新确定的转动和离心畸变常数用于在猎户座KL和人马座B2云中搜寻异氰酸乙酯的光谱特征。获得了这些高质量恒星形成区域中CHCHNCO的上限。
