Renner鈭扵eller and Fermi Resonance Interactions for the v3 = 1 and v7 = 2 Vibronic Levels in the A2螤u and X2螤g Electronic States of HC<

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• 作者：Ranjini Raghunandan ; Fabio J. Mazzotti ; Aaseef M. Esmail ; John P. Maier
• 刊名：Journal of Physical Chemistry A
• 出版年：2011
• 出版时间：September 1, 2011
• 年：2011
• 卷：115
• 期：34
• 页码：9365-9369
• 全文大小：713K
• 年卷期：v.115,no.34(September 1, 2011)
• ISSN：1520-5215

文摘

The excitation of the v₃ = 1 (蟽_g⁺ C鈭扖 stretch) and the v₇ = 2 (蟺_g² C鈮鈭扖 bend) modes in the A²螤_u electronic state of diacetylene cations results in Renner鈭扵eller (R鈭扵) and Fermi interactions. The 3₀¹ and 7₀² vibronic bands in the A²螤_u鈭扻²螤_g transition of HC₄H⁺ have been measured with rotational resolution using cavity ringdown spectroscopy in a supersonic slit jet discharge. The analysis yields T₀₀ = 20520.828(4) cm^鈭?, B鈥?= 0.14047(2) cm^鈭?, and A鈥?= 鈭?7.95(1) cm^鈭? for the v₃ = 1 and T₀₀ = 20573.659(4) cm^鈭?, B鈥?= 0.14018(3) cm^鈭?, and A鈥?= 鈭?1.55(1) cm^鈭? for the v₇ = 2 level in the A²螤_u electronic state. A vibronic analysis has been carried out taking into consideration the R鈭扵, spin鈭抩rbit, and Fermi resonance interactions between the 谓₃ and 谓₇ modes. The levels are fitted to the eigenvalues of an appropriate Hamiltonian matrix. This yields the vibrational frequencies 蠅₃鈥?= 811.8 cm^鈭? and 蠅₇鈥?= 403.2 cm^鈭?, Renner parameter 蔚₇鈥?= 0.065, Fermi coefficients W₁鈥?= 10.3 cm^鈭? and W₂鈥?= 5.1 cm^鈭?, and spin鈭抩rbit interaction constant A_SO鈥?= 鈭?1.1 cm^鈭?. A corresponding R鈭扵 analysis has been carried out for the X²螤_g ground state of HC₄H⁺ using data available in the literature [Callomon, J. H. Can. J. Phys. 1956, 34, 1046]. This gives 蠅₃鈥测€?= 956.2 cm^鈭?, 蠅₇鈥测€?= 435.4 cm^鈭?, 蔚₇鈥测€?= 0.028, W₁鈥测€?= 7.2 cm^鈭?, W₂鈥测€?= 10.9 cm^鈭?, and A_SO鈥测€?= 鈭?3.3 cm^鈭?.