NASA Ames Research Center, Moffett Field, California 94035-1000, USA.
J Phys Chem A. 2012 Sep 27;116(38):9582-90. doi: 10.1021/jp3073206. Epub 2012 Sep 18.
Besides the ν(1) O-H stretching mode at 3435 cm(-1) for HOCS(+), the fundamental vibrational frequencies for this cation and its HSCO(+) isomer have not been determined experimentally. Because these systems are analogues to HOCO(+), a detected interstellar molecule, and are believed to play an important role in reactions of OCS, which has also been detected in the interstellar medium, these cations are of importance to interstellar chemistry and reaction surface studies. This work provides the fundamental vibrational frequencies and spectroscopic constants computed with vibrational perturbation theory (VPT) at second order and the vibrational configuration interaction (VCI) method conjoined with the most accurate quartic force field (QFF) applied to date for these systems. Our computations match experiment to better than 2 cm(-1) for the known O-H stretch. Additionally, there is strong agreement in the prediction of the fundamentals across methods and choices of QFFs. The consistency in the computations and the correspondence for the known mode should give accurate reference data for the rovibrational spectra of these cations and their singly substituted isotopologues for D, (18)O, and (34)S.
除了 HOCS(+) 的 ν(1) O-H 伸缩模式在 3435 cm(-1)，这个阳离子及其 HSCO(+)异构体的基本振动频率尚未通过实验确定。由于这些系统类似于 HOCO(+)，一种已被检测到的星际分子，并且被认为在 OCS 的反应中起着重要作用，而 OCS 也已在星际介质中被检测到，因此这些阳离子对星际化学和反应表面研究很重要。这项工作提供了用二阶振动微扰理论 (VPT) 和迄今为止应用的最精确的四次力场 (QFF) 联合的振动组态相互作用 (VCI) 方法计算得到的基本振动频率和光谱常数。对于已知的 O-H 伸缩，我们的计算与实验的匹配精度优于 2 cm(-1)。此外，不同方法和 QFF 选择的基本模式的预测也有很强的一致性。计算的一致性和已知模式的对应性应该为这些阳离子及其单取代同位素 D、(18)O 和 (34)S 的 rovibrational 光谱提供准确的参考数据。
