Ethanethiol, also known as ethyl mercaptan, is an organosulfur compound that appears as a colorless liquid with a distinctive odor. It has been detected in the interstellar medium, and its self‐association has been the subject of a few known experimental studies, where the SH vibrational mode was used. However, unlike the analogous ethanol dimer, the ethanethiol dimer has not been thoroughly explored theoretically. In this study, ethanethiol and dimers were investigated using the MP2 method with various basis sets to determine the properties and stability of these structures. For the monomer, both trans and gauche structures were computed, with the gauche conformer being more stable, consistent with the available data in the literature. Local mode decomposition analysis of monomers showed that the CH2 rocking mode, associated with the CSH bending, is present only for the gauche isomer aligning with the experimental assignments. Furthermore, eight stable dimer configurations were identified and categorized into three groups: trans–trans, gauche–gauche, and trans–gauche isomers. Among these, the trans–gauche isomer was found to be the most stable. Dispersion is the dominant term for the ethanethiol dimer.

中文翻译：

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MP2 水平乙硫醇单体和二聚体的红外光谱：表征二聚体形成和氢键


乙硫醇，也称为乙硫醇，是一种有机硫化合物，呈无色液体，具有独特的气味。它已在星际介质中被检测到，其自缔合已成为一些已知实验研究的主题，其中使用了 SH 振动模式。然而，与类似的乙醇二聚体不同，乙硫醇二聚体在理论上尚未得到彻底探索。在这项研究中，使用具有不同基集的 MP2 方法研究了乙硫醇和二聚体，以确定这些结构的性质和稳定性。对于单体，计算了 trans 和 gauche 结构，其中 gauche 构象异构体更稳定，与文献中的可用数据一致。单体的局部模式分解分析表明，与 CSH 弯曲相关的 CH2 摇摆模式仅存在于与实验分配对齐的 gauche 异构体中。此外，确定了 8 种稳定的二聚体构型，并将其分为三组：trans-trans、gauche-gauche 和 trans-gauche 异构体。其中，发现 trans-gauche 异构体是最稳定的。分散是乙硫醇二聚体的主要术语。