Ion-Pair Dissociation Dynamics of Cl2 in the Range 13.26−13.73 eV Studied by Using XUV Laser and the Velocity Map Imaging Method

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• 作者：Yusong Hao ; Chang Zhou ; Yuxiang Mo*
• 刊名：Journal of Physical Chemistry A
• 出版年：2009
• 出版时间：March 19, 2009
• 年：2009
• 卷：113
• 期：11
• 页码：2294-2303
• 全文大小：377K
• 年卷期：v.113,no.11(March 19, 2009)
• ISSN：1520-5215

文摘

The ion-pair dissociation dynamics of Cl₂ in the range 13.26−13.73 eV have been studied employing coherent extreme ultraviolet radiation (XUV) and the velocity map imaging method. The Cl⁻(¹S₀) ion-pair yield spectrum has been measured, and 80 velocity map images of Cl⁻(¹S₀) have been recorded for the strong peaks in the spectrum. From the images, two dissociation channels corresponding to Cl⁻(¹S₀) + Cl⁺(³P_j) and Cl⁻(¹S₀) + Cl⁺(¹D₂) have been found. The branching ratios among the fragments Cl⁺(³P_0,1), Cl⁺(³P₂), and Cl⁺(¹D₂) and their corresponding anisotropy parameters β have been determined. It is concluded that the ion-pair dissociation occurs via the predissociation of Rydberg states and its dynamics strongly depend on the excitation energies. The perpendicular and parallel transitions correspond to the excitation to two major Rydberg series converging to ion-core Cl₂⁺(A²Π_u),...σ_g²π_u³π_g⁴[A²Π_u]nsσ_g, ¹Π_u (n = 6,7), and...σ_g²π_u³π_g⁴[A²Π_u]ndπ_g, ¹Σ_u⁺(n = 4,5), respectively. For the production of fragments Cl⁺(¹D₂), it is proposed that the perpendicular transitions are from the excitation to Rydberg states [A²Π_u]nsσ_g, ¹Π_u that is predissociated by ion-pair state 2¹Π_u, while the parallel transitions are from the excitation to [A²Π_u]ndπ_g, ¹Σ_u⁺ that interacts with ion-pair states 0_u⁺(¹D₂), 0_u⁺(³P₂), and 0_u⁺(³P₀).