Analysis of the Rotational Structure in the High-Resolution Infrared Spectrum of trans-Hexatriene-1-13C1: A Semiexperimental Equilibrium Structure for the C6 Ba

详细信息    查看全文

• 作者：Norman C. Craig ; Hengfeng Tian ; Thomas A. Blake
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：March 29, 2012
• 年：2012
• 卷：116
• 期：12
• 页码：3148-3155
• 全文大小：385K
• 年卷期：v.116,no.12(March 29, 2012)
• ISSN：1520-5215

文摘

trans-Hexatriene-1-¹³C₁ (tHTE-1-¹³C₁) has been synthesized, and its high-resolution (0.0015 cm^鈥?) infrared spectrum has been recorded. The rotational structure in the C-type bands for 谓₂₆ at 1011 cm^鈥? and 谓₃₀ at 894 cm^鈥? has been analyzed. To the 1458 ground state combination differences from these bands, ground state rotational constants were fitted to a Watson-type Hamiltonian to give A₀ = 0.8728202(9), B₀ = 0.0435868(4), and C₀ = 0.0415314(2) cm^鈥?. Upper state rotational constants for the 谓₃₀ band were also fitted. Predictions of the ground state rotational constants for tHTE-1-¹³C₁ from a B3LYP/cc-pVTZ model with scale factors based on the normal species were in excellent agreement with observations. Similar good agreement was found between predicted and observed ground state rotational constants for the three ¹³C₁ isotopologues of cis-hexatriene, as determined from microwave spectroscopy. Equilibrium rotational constants for tHTE and its three ¹³C₁ isotopologues, of which two were predicted, were used to find a semiexperimental equilibrium structure for the C₆ backbone of tHTE. This structure shows increased structural effects of 蟺-electron delocalization in comparison with butadiene and some differences from the cis isomer of HTE. Structures predicted with the MP2/cc-pVTZ model are also compared.