Accurate Semiexperimental Structure of 1,3,4-Oxadiazole by the Mixed Estimation Method

详细信息    查看全文

• 作者：Jean Demaison ; Michaela K. Jahn ; Emilio J. Cocinero ; Alberto Lesarri ; Jens-Uwe Grabow ; Jean-Claude Guillemin ; Heinz Dieter Rudolph
• 刊名：The Journal of Physical Chemistry A
• 出版年：2013
• 出版时间：March 14, 2013
• 年：2013
• 卷：117
• 期：10
• 页码：2278-2284
• 全文大小：260K
• 年卷期：v.117,no.10(March 14, 2013)
• ISSN：1520-5215

文摘

In order to determine an accurate equilibrium structure for 1,3,4-oxadiazole, microwave transitions and ground-state rotational constants are reported for the parent species and for the ¹⁸O isotopologue measured in natural abundance. These rotational constants along with those of the ¹³C, ¹⁵N, and D₁ species were used together with vibration鈥搑otation constants calculated from a cubic force field calculated at the B3LYP/6-311+G(3df,2pd) level of theory to derive a semiexperimental equilibrium structure. However, the results of this fit were not satisfactory; therefore, the structure was later significantly improved by the mixed estimation method. In this method, internal coordinates from good-quality quantum chemical calculations (with appropriate uncertainties) are fitted simultaneously with moments of inertia of the full set of isotopologues. The accuracy of this structure has been confirmed by using an extrapolation technique. All elements of the ¹⁴N nuclear quadrupole coupling tensor have been determined.