Photodissociation Dynamics of Diacetylene Rydberg States

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• 作者：Hongzhen Wang ; Shengrui Yu ; Shu Su ; Dongxu Dai ; Kaijun Yuan ; Xueming Yang
• 刊名：Journal of Physical Chemistry A
• 出版年：2015
• 出版时间：November 19, 2015
• 年：2015
• 卷：119
• 期：46
• 页码：11313-11319
• 全文大小：491K
• ISSN：1520-5215

文摘

The state-selective photodissociation of diacetylene (C₄H₂) was studied in the wavelength range of 127.5鈥?64.4 nm by high-resolution Rydberg H atom time-of-flight spectroscopy measurements. In the wavelength region, two Rydberg series nR and nR鈥?were state-selectively excited using tunable vacuum-ultraviolet laser radiation. In all photolysis wavelengths, two decay channels with different dissociation dynamics were observed. In one channel, the characteristic and isotropic translational energy distributions with a peak around 1800 cm^鈥? can be found, suggesting statistical dissociation through internal conversion (IC) from the Rydberg state to the ground state and then dissociation on the ground-state surface. In contrast to this, in the second channel, nonstatistical and anisotropic translational energy distributions were observed, possibly through IC to the excited repulsive state. The vibrational progressions of C₄H (A²螤) products have also been observed and assigned to the CCC bend and C鈮 stretch progressions in the second channel at 3R Rydberg states.