Inner-valence excited and multiply excited states of molecular oxygen around the double-ionization potential as probed by a pair of fluorescence photons
Inner-valence excited and multiply excited states of molecular oxygen around the double-ionization potential as probed by a pair of fluorescence photons
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DOI：
10.1088/0953-4075/42/5/055101
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发表时间：
2009-03
期刊：
影响因子：
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通讯作者：
T. Odagiri;H. Miyagi;M. Murata;H. Fukuzawa;M. Kurokawa;M. Kitajima;N. Kouchi
中科院分区：
文献类型：
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作者：
T. Odagiri;H. Miyagi;M. Murata;H. Fukuzawa;M. Kurokawa;M. Kitajima;N. Kouchi
利用光子-光子符合方法、（γ，2γ）方法，测量了在23-47 eV范围内，O_2光激发中产生一对荧光光子的截面与光子对发射立体角的微分关系，研究O2的内价激发态和多重激发态作为超激发态。在测得的无电离截面曲线中，在29、36、38和44 eV附近新发现了O2的四个超激发态，它们具有3 <$−u或3 <$u对称性。结果表明，它们是内价激发态和多重激发态。有两点值得注意：（1）在双电离势（36.13eV）以上的能量范围内，存在O2解离成中性碎片的超激发态;（2）在双电离势附近，双微分截面随入射光子能量的增加而大幅度减小，这两个结果都与我们以前对N_2的（γ，2γ）实验结果作了比较。详细讨论了（2）的起源。
The cross sections for the generation of a pair of fluorescence photons in the photoexcitation of O2 differential with respect to solid angles for the emission of the photon pair have been measured as a function of incident photon energy in the range 23–47 eV using the photon–photon coincidence method, the (γ, 2γ) method, to investigate the inner-valence excited states and multiply excited states of O2 as superexcited states. Four superexcited states of O2 with the 3Σ−u or 3Πu symmetry have been newly found around 29, 36, 38 and 44 eV in the measured cross section curve free from ionization. It turns out that they are inner-valence excited states and multiply excited states. Two remarkable points are shown: (1) there exist superexcited states of O2 dissociating into neutral fragments even in the energy range above the double-ionization potential of O2 at 36.13 eV and (2) the values of the doubly differential cross sections decrease to a large extent around the double-ionization potential with increasing incident photon energy, both of which have been compared with the results of N2 by our previous (γ, 2γ) experiment. The origin of (2) is discussed in detail.