The most prominent pure rotational transitions of the prochiral, possibly prebiotic molecule acetylacetylene are recorded in the frequency range of 6.5–26.5 GHz for a reliable spectral characterization prerequisite to a possible extraterrestrial observation. Therefore, three different approaches for global fitting of the vibrational ground state are applied to analyze the experimentally determined transition frequencies using the programs SPFIT, XIAM and ERHAM corresponding to different theoretical treatments solving the internal rotation problem.

Furthermore, the resulting internal rotation parameter V₃ is compared to those other substituted acetyl species, and derivatives of butynes and possible explanations for the observed trends are given. For the substituted acetyl species, the spectra of acetylfluoride, -chloride, -bromide and -iodide are reanalyzed.

The obtained rotational constants have been interpreted in terms of characterizing the geometric structure. A correlation between the tunneling parameter ε₁ and V₃ of several molecular species displaying spectral internal rotation splitting patterns has been found and quantified. This relationship can simplify the analysis of vibrational ground state rotational spectra in finding a suitable starting point for the fitting procedure using the program ERHAM, which is the predestined choice to analyze and predict signal positions up to very high quantum numbers. Being able to predict those signal positions is crucial for a possible comprehensive astronomical identification and subsequent application as an astrophysical probe for the conditions in interstellar molecular clouds.

前手性分子（可能是益生元）乙酰乙炔的最明显的纯旋转跃迁记录在6.5-26.5 GHz的频率范围内，这是可能的地球外观测的可靠光谱表征的前提。因此，使用三种不同的方法来对振动基态进行整体拟合，以使用SPFIT，XIAM和ERHAM程序来分析实验确定的过渡频率，这些程序对应于解决内部旋转问题的不同理论方法。

此外，将所得的内部旋转参数V ₃与那些其他取代的乙酰基种类进行比较，并给出了丁炔的衍生物以及观察到的趋势的可能解释。对于取代的乙酰基，重新分析了乙酰氟，-氯化物，-溴化物和-碘化物的光谱。

已经从表征几何结构的角度解释了获得的旋转常数。隧道参数之间的相关性ε ₁和V ₃已发现并量化了几种显示光谱内部旋转分裂图谱的分子种类。通过使用程序ERHAM，这种关系可以简化振动基态旋转谱的分析，找到适合拟合过程的起点，这是分析和预测高达非常高的量子数的信号位置的首选。能够预测这些信号位置对于可能的全面天文鉴定和随后作为星际分子云中的天体探测探针的应用至关重要。