HxCyOz isomerization energies

It has been recently demonstrated that there is a high statistical correlation between the relative energies of isomers and their relative abundances in the interstellar medium (ISM). In the present work, we use the high-level W2-F12 thermochemical protocol to obtain accurate isomerization energies for a set of 109 HxCyOz isomers, 18 of which have been observed in the ISM so far. We use our benchmark isomerization energies to (i) rationalize the presence of the isomers that have been detected and (ii) predict which new isomers are likely to be detected in the future. We find that the energetically most stable isomers of H2C3O (1,2-propadien-1-one), H8C3O (2-propanol), and H6C3O2 (propanoic acid) have not been observed, despite the fact that higher-energy isomers of these chemical formulas have been detected in the ISM. The dipole moments of these isomers are sufficiently large that these species should be observed using microwave spectroscopy techniques. <br>近期已有研究表明，异构体的相对能量与其在星际介质（ISM）中的相对丰度之间存在显著的统计相关性。在本研究中，我们采用高精度W2-F12热化学方案，为包含109种HₓCᵧO_z异构体的数据集计算了精确的异构化能，其中截至目前已有18种在星际介质中被观测到。我们利用该基准异构化能完成两项任务：(i) 阐释已被探测到的异构体的存在合理性；(ii) 预测未来有望在星际介质中被探测到的新型异构体。研究发现，尽管对应分子式的高能异构体已在星际介质中被探测到，但H₂C₃O（1,2-丙二烯-1-酮）、H₈C₃O（2-丙醇）以及H₆C₃O₂（丙酸）在能量上最稳定的异构体尚未被观测到。这些未被观测到的异构体具有足够大的偶极矩，因此可通过微波波谱技术实现探测。