High-resolution C 1s photoelectron spectra of methane.
High-resolution C 1s photoelectron spectra of methane.
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甲烷的高分辨率 C 1s 光电子能谱。
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发表时间：
1996
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通讯作者：
A. Bradshaw
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作者：
H. M. Köppe;B. S. Itchkawitz;A. Kilcoyne;J. Feldhaus;B. Kempgens;A. Kivimäki;M. Neeb;A. Bradshaw
在阈值和385 eV光子能量之间的高能分辨率下，测量了甲烷（${\ mathm {CH}}_{4}$）的c1s部分光电离截面和光电子角分布。通过对c1 ${\mathit{s}}^{\ mathm {\ensuremath{-}}}1}$光电子线的振动精细结构分析，确定了${\ mathm {CH}}_{4}^{+}$离子的振动能量为396\ifmmode\pm\else\textpm\fi{}2 meV，平衡键长为1.039(\ifmmode\pm\else\textpm\fi{}0.001) \AA{}。寿命展宽为83(\ifmmode\pm\else\textpm\fi{}10) meV。光吸收截面刚好高于阈值的弱特征不会像典型的形状共振那样影响振动精细结构。因此，我们认为这是由于C (1s${)}^{\mathrm{\ensuremath{-}}1}$(Val${)}^{\mathrm{\ensuremath{-}}1}$(Ryd${)}_{\mathit{a}}^{1}$(Ryd${)}_{\mathit{b}}^{1}$的双激发态，最近的奥歇衰变研究支持这一赋值。对震荡结构的测量揭示了六条卫星线，其中一条在阈值处强度强烈增加，从而指出了共轭震荡过程的存在。1996美国物理学会。
The C 1s partial photoionization cross section and photoelectron angular distribution of methane (${\mathrm{CH}}_{4}$) have been measured with high-energy resolution between threshold and 385 eV photon energy. From the analysis of the vibrational fine structure on the C 1${\mathit{s}}^{\mathrm{\ensuremath{-}}1}$ photoelectron line a vibrational energy of 396\ifmmode\pm\else\textpm\fi{}2 meV and an equilibrium bond length of 1.039(\ifmmode\pm\else\textpm\fi{}0.001) \AA{} for the ${\mathrm{CH}}_{4}^{+}$ ion have been determined. The lifetime broadening was found to be 83(\ifmmode\pm\else\textpm\fi{}10) meV. The weak feature in the photoabsorption cross section just above threshold does not influence the vibrational fine structure in a way typical for a shape resonance. We therefore suggest that it is due to doubly excited states of the type C (1s${)}^{\mathrm{\ensuremath{-}}1}$(Val${)}^{\mathrm{\ensuremath{-}}1}$(Ryd${)}_{\mathit{a}}^{1}$(Ryd${)}_{\mathit{b}}^{1}$, an assignment which is supported by recent Auger decay studies. Measurements of the shakeup structure revealed six satellite lines, one of which increases strongly in intensity at threshold, thus pointing to the existence of a conjugate shakeup process. \textcopyright{} 1996 The American Physical Society.