New Diagnostic of the Most Populated Conformer of Tetrahydrofuran in the Gas Phase

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• 作者：Tiecheng Yang ; Guolin Su ; Chuangang Ning ; Jingkang Deng ; Feng Wang ; Shufeng Zhang ; Xueguang Ren ; Yanru Huang
• 刊名：Journal of Physical Chemistry A
• 出版年：2007
• 出版时间：June 14, 2007
• 年：2007
• 卷：111
• 期：23
• 页码：4927 - 4933
• 全文大小：315K
• 年卷期：v.111,no.23(June 14, 2007)
• ISSN：1520-5215

文摘

The most populated conformer of tetrahydrofuran (C₄H₈O) has been diagnosed as the C_s conformer in thepresent study, jointly using experimental electron momentum spectroscopy (EMS) and quantum mechanics.Our B3LYP/6-311++G** model indicates that the C₁ conformation, which is one of the three possibleconformations of tetrahydrofuran produced by pseudorotation in the gas phase, is a transition state due to itsimaginary frequencies, in agreement with the prediction from a recent ab initio MP2/aug-cc-pVTZ study (J.Chem. Phys. 2005, 122, 204303). The study has identified the fingerprint of the highest occupied molecularorbital (HOMO) of the C_s (12a') conformer as the most populated conformer. The identification of the C_sstructure, therefore, leads to the orbital-based assignment of the ionization binding energy spectra oftetrahydrofuran for the first time, on the basis of the outer valence Green function OVGF/6-31G* model andthe density functional theory (DFT) SAOP/ET-PVQZ model. The present study explores an innovative approachto study molecular stabilities. It also indicates that energetic properties are not always the most appropriatemeans to study conformer-rich biological systems.