Tschöpe Martin, Schröder Benjamin, Erfort Sebastian, Rauhut Guntram
Institute for Theoretical Chemistry, University of Stuttgart, Stuttgart, Germany.
Front Chem. 2021 Jan 6;8:623641. doi: 10.3389/fchem.2020.623641. eCollection 2020.
From an astrochemical point of view ketenimine (CHCNH) is a complex organic molecule (COM) and therefore likely to be a building block for biologically relevant molecules. Since it has been detected in the star-forming region Sagittarius B2(N), it is of high relevance in this field. Although experimental data are available for certain bands, for some energy ranges such as above 1200 cm reliable data virtually do not exist. In addition, high-level calculations are neither reported for ketenimine nor for one of its deuterated isotopologues. In this paper, we provide for the first time data from accurate quantum chemical calculations and a thorough analysis of the full rovibrational spectrum. Based on high-level potential energy surfaces obtained from explicitly correlated coupled-cluster calculations including up to 4-mode coupling terms, the (ro)vibrational spectrum of ketenimine has been studied in detail by variational calculations relying on rovibrational configuration interaction (RVCI) theory. Strong Fermi resonances were found for all isotopologues. Rovibrational infrared intensities have been obtained from dipole moment surfaces determined from the distinguishable cluster approximation. A comparison of the spectra of the CHCNH molecule with experimental data validates our results, but also reveals new insight about the system, which shows very strong Coriolis coupling effects.
从天体化学的角度来看，乙烯亚胺（CHCNH）是一种复杂有机分子（COM），因此很可能是与生物相关分子的组成部分。由于它已在恒星形成区域人马座B2（N）中被检测到，所以在该领域具有高度相关性。尽管某些波段有实验数据，但在某些能量范围，例如高于1200 cm的范围，几乎不存在可靠数据。此外，既没有关于乙烯亚胺也没有关于其一种氘代同位素分子的高水平计算报告。在本文中，我们首次提供了精确量子化学计算的数据以及对完整振转光谱的全面分析。基于从显式相关耦合簇计算获得的包含高达4模式耦合项的高水平势能面，依靠振转组态相互作用（RVCI）理论通过变分计算详细研究了乙烯亚胺的（振）转光谱。在所有同位素分子中都发现了强烈的费米共振。振转红外强度是从由可区分簇近似确定的偶极矩面获得的。将CHCNH分子的光谱与实验数据进行比较验证了我们的结果，但也揭示了关于该系统的新见解，该系统显示出非常强的科里奥利耦合效应。
