Institute for Molecular Science, Nishigo-Naka 38, Myodaiji, Okazaki 444-8585, Japan.
J Chem Phys. 2011 Oct 21;135(15):154307. doi: 10.1063/1.3651082.
We report on theoretical Auger electron kinetic energy distribution originated from sequential two-step Auger decays of molecular double core-hole (DCH) state, using CH(4), NH(3), and H(2)CO molecules as representative examples. For CH(4) and NH(3) molecules, the DCH state has an empty 1s inner-shell orbital and its Auger spectrum has two well-separated components. One is originated from the 1st Auger transition from the DCH state to the triply ionized states with one core hole and two valence holes (CVV states) and the other is originated from the 2nd Auger transition from the CVV states to quadruply valence ionized (VVVV) states. Our result on the NH(3) Auger spectrum is consistent with the experimental spectrum of the DCH Auger decay observed recently [J. H. D. Eland, M. Tashiro, P. Linusson, M. Ehara, K. Ueda, and R. Feifel, Phys. Rev. Lett. 105, 213005 (2010)]. In contrast to CH(4) and NH(3) molecules, H(2)CO has four different DCH states with C1s(-2), O1s(-2), and C1s(-1)O1s(-1) (singlet and triplet) configurations, and its Auger spectrum has more complicated structure compared to the Auger spectra of CH(4) and NH(3) molecules. In the H(2)CO Auger spectra, the C1s(-1)O1s(-1) DCH → CVV Auger spectrum and the CVV → VVVV Auger spectrum overlap each other, which suggests that isolation of these Auger components may be difficult in experiment. The C1s(-2) and O1s(-2) DCH → CVV Auger components are separated from the other components in the H(2)CO Auger spectra and can be observed in experiment. Two-dimensional Auger spectrum, representing a probability of finding two Auger electrons at specific pair of energies, may be obtained by four-electron coincidence detection technique in experiment. Our calculation shows that this two-dimensional spectrum is useful in understanding contributions of CVV and VVVV states to the Auger decay of molecular DCH states.
我们报告了源自分子双芯空(DCH)态顺序双步 Auger 衰变的理论 Auger 电子动能分布，使用 CH(4)、NH(3)和 H(2)CO 分子作为代表性例子。对于 CH(4)和 NH(3)分子，DCH 态具有空的 1s 内壳轨道，其 Auger 谱具有两个明显分离的分量。一个源自 DCH 态到具有一个芯空和两个价空(CVV 态)的三重离子化态的第一 Auger 跃迁，另一个源自 CVV 态到四重价离子化( VVVV)态的第二 Auger 跃迁。我们对 NH(3)Auger 谱的结果与最近观察到的 DCH Auger 衰变的实验谱[J. H. D. Eland、M. Tashiro、P. Linusson、M. Ehara、K. Ueda 和 R. Feifel，Phys. Rev. Lett. 105，213005 (2010)]一致。与 CH(4)和 NH(3)分子相比，H(2)CO 具有具有 C1s(-2)、O1s(-2)和 C1s(-1)O1s(-1)(单重态和三重态)构型的四个不同的 DCH 态，其 Auger 谱与 CH(4)和 NH(3)分子的 Auger 谱相比具有更复杂的结构。在 H(2)CO Auger 谱中，C1s(-1)O1s(-1)DCH→CVV Auger 谱和 CVV→VVVV Auger 谱相互重叠，这表明这些 Auger 分量在实验中可能难以分离。C1s(-2)和 O1s(-2)DCH→CVV Auger 分量与 H(2)CO Auger 谱中的其他分量分离，可以在实验中观察到。二维 Auger 谱代表在特定能量对中找到两个 Auger 电子的概率，可以通过四电子符合探测技术在实验中获得。我们的计算表明，这种二维谱对于理解 CVV 和 VVVV 态对分子 DCH 态 Auger 衰变的贡献很有用。
