The elucidation of conformations and relative potential energies (rPEs) of small molecules has a long history across a diverse range of fields. Periodically, it is helpful to revisit what conformations have been investigated and to provide a consistent theoretical framework for which clear comparisons can be made. In this paper, we compute the minima, first- and second-order saddle points, and torsion-coupled surfaces for methanol, ethanol, propan-2-ol, and propanol using consistent high-level MP2 and CCSD(T) methods. While for certain molecules more rigorous methods were employed, the CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pV5Z theory level was used throughout to provide relative energies of all minima and first-order saddle points. The rPE surfaces were uniformly computed at the CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVTZ level. To the best of our knowledge, this represents the most extensive study for alcohols of this kind, revealing some new aspects. Especially for propanol, we report several new conformations that were previously not investigated. Moreover, two metrics are included in our analysis that quantify how the selected surfaces are similar to one another and hence improve our understanding of the relationship between these alcohols.

中文翻译：

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再谈小酒精：最小，一阶和二阶鞍点和扭转耦合表面的CCSD（T）相对势能

阐明小分子的构象和相对势能（rPEs）在不同领域中都有悠久的历史。定期地，重新审视已经研究过的构象并提供一个可以进行清晰比较的一致的理论框架是有帮助的。在本文中，我们使用一致的高级MP2和CCSD（T）方法来计算甲醇，乙醇，丙-2-醇和丙醇的最小，一阶和二阶鞍点以及扭转耦合表面。虽然对于某些分子采用了更严格的方法，但始终使用CCSD（T）/ aug-cc-pVTZ // MP2 / aug-cc-pV5Z理论水平来提供所有最小和一阶鞍点的相对能量。rPE表面在CCSD（T）/ aug-cc-pVTZ // MP2 / aug-cc-pVTZ级别进行了统一计算。据我们所知，这代表了对这类醇类的最广泛的研究，揭示了一些新的方面。尤其是对于丙醇，我们报告了一些以前没有研究过的新构象。此外，我们的分析中包含两个指标，这些指标可以量化所选表面如何彼此相似，从而提高我们对这些醇之间关系的理解。