VUV Photodissociation Dynamics of Nitrous Oxide: The O(1SJ=0) and O(3PJ=2,1,0) Product Channels

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• 作者：Shengrui Yu ; Daofu Yuan ; Wentao Chen ; Xueming Yang ; Xingan Wang
• 刊名：Journal of Physical Chemistry A
• 出版年：2015
• 出版时间：July 23, 2015
• 年：2015
• 卷：119
• 期：29
• 页码：8090-8096
• 全文大小：565K
• ISSN：1520-5215

文摘

Vacuum ultraviolet photodissociation dynamics of nitrous oxide was investigated using the time-sliced velocity ion imaging technique. Images of the O(¹S_J=0) and the O(³P_J=2,1,0) products were measured at nine photolysis wavelengths from 124.44 to 133.20 nm, respectively. Three main dissociation channels: O(¹S₀) + N₂(X¹危_g⁺), O(³P_J=2,1,0) + N₂(A³危_u⁺), and O(³P_J=2,1,0) + N₂(B³螤_g) were observed and identified in the product images where vibrational states of N₂ were fully resolved. Product total kinetic energy releases and angular distributions were acquired. In all product channels, the branching ratios of vibrational states of N₂ products were determined. In addition, the O(³P_J=2,1,0) + N₂(A³危_u⁺)/O(³P_J=2,1,0) + N₂(B³螤_g) branching ratios were determined. We found that in the O(³P_J=2,1,0) channels the O(³P_J=2,1,0) + N₂(B³螤_g) channel becomes dominant at long photolysis wavelength, indicating a strong coupling between the singlet D(¹危_g⁺) state and the triplet ³螤 state. For both O(¹S₀) and O(³P_J=2,1,0) products, the derived angular anisotropy parameters (尾 values) are very close to 2 at lower vibrational states of the correlated N₂ electronic states and gradually decrease with the increasing vibrational quantum number. These behaviors suggest that the photodissociation processes are primarily governed by a fast dissociation in a linear geometry, while the N₂ products at excited vibrational states are very likely produced via a more bent transition state.