Motiyenko Roman A, Margulès Laurent, Senent Maria L, Guillemin Jean-Claude
Laboratoire de Physique des Lasers, Atomes et Molécules, UMR 8523 , CNRS - Université de Lille , F-59655 Villeneuve d'Ascq Cedex , France.
Departamento de Química y Física Teóricas , Instituto de Estructura de la Materia, IEM-C.S.I.C. , Serrano 121 , Madrid 28006 , Spain.
J Phys Chem A. 2018 Mar 29;122(12):3163-3169. doi: 10.1021/acs.jpca.7b12051. Epub 2018 Mar 20.
Cyanoacetylene, HCC-CN is a ubiquitous molecule in the Universe. However, its interstellar chemistry is not well understood and its understanding requires laboratory data including rotational spectroscopy of possible products coming from a reaction with another compounds. In this study we present the first spectroscopic characterization of gauche conformation of 4-hydroxy-2-butynenitrile (HOCHCCCN), a formal adduct of cyanoacetylene on formaldehyde, in the frequency range up to 500 GHz. The analysis of the rotational spectrum was complicated by internal rotation of the OH group that connects two equivalent gauche configurations. The spectral assignment was aided by high-level quantum chemical calculations that were particularly useful in the interpretation of torsional-rotational part of the problem. The applied reduced-axis-system (RAS) formalism allowed fitting within experimental accuracy the lines with K < 18. We also present the method of search for initial global solution of torsional-rotational problem within RAS formalism. Accurate spectroscopic parameters obtained in this study provide a reliable basis for the detection of 4-hydroxy-2-butynenitrile in the interstellar medium.
氰基乙炔（HCC-CN）是宇宙中一种普遍存在的分子。然而，其星际化学过程尚未得到充分理解，对其进行了解需要实验室数据，包括与其他化合物反应可能产生的产物的转动光谱。在本研究中，我们展示了4-羟基-2-丁炔腈（HOCHCCCN）的gauche构象的首次光谱表征，它是氰基乙炔与甲醛的一种形式加合物，频率范围高达500 GHz。连接两个等效gauche构型的OH基团的内旋转使转动光谱的分析变得复杂。高水平量子化学计算辅助了光谱归属，这在解释该问题的扭转-转动部分时特别有用。应用的简化轴系（RAS）形式允许在实验精度范围内拟合K < 18的谱线。我们还提出了在RAS形式内寻找扭转-转动问题初始全局解的方法。本研究中获得的精确光谱参数为在星际介质中检测4-羟基-2-丁炔腈提供了可靠依据。
