Quartic Force Field Rovibrational Analysis of Protonated Acetylene, C2H3+, and Its Isotopologues

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• 作者：Ryan C. Fortenberry ; Xinchuan Huang ; T. Daniel Crawford ; Timothy J. Lee
• 刊名：Journal of Physical Chemistry A
• 出版年：2014
• 出版时间：August 28, 2014
• 年：2014
• 卷：118
• 期：34
• 页码：7034-7043
• 全文大小：290K
• ISSN：1520-5215

文摘

Protonated acetylene, C₂H_{class="stack">3}^{class="stack">+}, is among the simplest carbocations. Comprehensive experimental or highly accurate computational spectroscopic data is lacking for this system due to its inherent complexities. Utilizing state-of-the-art quartic force fields (QFFs), the spectroscopic constants and fundamental vibrational frequencies are provided in this work for the nonclassical, bridged, cyclic global minimum. The rotational constants match experiment to better than 0.1%, and the computed 谓₂ antisymmetric HCCH stretch is less than 3.0 cm^鈥? different from experiment. Hence, the rovibrational spectroscopic data provided herein for c-C₂H_{class="stack">3}^{class="stack">+} and its deuterated isotopologues enrich the chemical understanding of this system. Unfortunately, the same rovibrational spectroscopic data is not as trustworthy for the classical, linear form of protonated acetylene due to the shallow well in which it resides on the potential energy surface. However, spectroscopic data are provided for this isomer in the Supporting Information to enhance future studies.