Vacuum Ultraviolet Photodissociation Dynamics of Isocyanic Acid: The Hydrogen Elimination Channel

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• 作者：Shengrui Yu ; Shu Su ; Dongxu Dai ; Kaijun Yuan ; Xueming Yang
• 刊名：Journal of Physical Chemistry A
• 出版年：2013
• 出版时间：December 19, 2013
• 年：2013
• 卷：117
• 期：50
• 页码：13564-13571
• 全文大小：427K
• 年卷期：v.117,no.50(December 19, 2013)
• ISSN：1520-5215

文摘

Photodissociation dynamics of the H-atom channel from HNCO photolysis between 124 and 137 nm have been studied using the H-atom Rydberg tagging time-of-flight technique. Product translational energy distributions and angular distributions have been determined. Two dissociation channels, H + NCO (X²螤) and H + NCO(A²危⁺), have been observed. The former channel involves two different dissociation pathways; one is a slow predissociation pathway through internal conversion from the excited state to the S₀ state, and the other is a fast predissociation pathway through internal conversion from the excited state to the S₁ state. The latter channel dominates by a prompt dissociation via coupling to the S₂ state. As the photon energy increases, dissociation on the ground state S₀ becomes dominant. Vibrational structures are observed in both the NCO(X) and NCO(A) channels, which can be assigned to the bending mode excitation with some stretching vibrational excitation.