Experimental evidence for the existence of an electronically excited state of the proposed dihydrogen radical cation He-H-H-He+.
Experimental evidence for the existence of an electronically excited state of the proposed dihydrogen radical cation He-H-H-He+.
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所提出的二氢自由基阳离子 He-H-H-He 存在电子激发态的实验证据。
DOI：
10.1002/chem.200802545
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
P. Scheier
中科院分区：
文献类型：
--
作者：
S. Jaksch;F. Ferreira da Silva;S. Denifl;O. Echt;T. Märk;P. Scheier
弱者的生存：Uggerud及其同事最近在该杂志上提出了一类新的中心对称自由基阳离子的存在，其中H（2）桥接两个相同的主族元素。通过在低于开尔文温度的氦纳米滴中生长复合物，我们获得了这类最弱结合成员He-H-H-He（+）（见图）存在的实验证据，尽管处于亚稳态，电子激发态。Krapp等人，欧洲化学品J. 2008，14，4028）提出了一类新的自由基阳离子的存在，其中二氢桥连两个相同的主族元素。在电子碰撞电离掺杂有一个或多个H（2）分子的氦纳米液滴时，我们观察到各种He（x）H（y）（+）团簇离子，包括He（2）H（2）（+），其属于所提出的自由基阳离子类别。质量分析的动能扫描显示，离子是亚稳态的，它在质谱仪的无场区解离。一个反应是进入HeH（2）（+）+ He，释放15+/-4 meV的低动能。令人惊讶的是，观察到另一种单分子反应，形成HeH（+）+ HeH（或He + H）。这种反应的概率要高出一个数量级，平均动能释放要大四倍。这些发现表明存在亚稳态电子激发态;它们与He-H-H-He（+）的线性中心对称离子结构一致。
Survival of the weakest: The existence of a new class of centrosymmetric radical cations in which H(2) bridges two identical main group elements was recently proposed in this journal by Uggerud and co-workers. By growing complexes inside helium nanodroplets at subkelvin temperatures, we obtained experimental evidence for the existence of the most weakly bound member of this class, He-H-H-He(+) (see picture), although in a metastable, electronically excited state.In a recent report, Uggerud and co-workers (A. Krapp et al., Chem. Eur. J. 2008, 14, 4028) proposed the existence of a new class of radical cations in which a dihydrogen bridges two identical main group elements. Upon electron impact ionization of helium nanodroplets doped with one or more H(2) molecules we observe various He(x)H(y) (+) cluster ions, including He(2)H(2) (+), which would belong to the proposed class of radical cations. Mass-analyzed kinetic energy scans reveal that the ion is metastable; it dissociates in the field-free region of the mass spectrometer. One reaction is into HeH(2) (+) + He with a low kinetic energy release of 15+/-4 meV. Surprisingly, another unimolecular reaction is observed, into HeH(+) + HeH (or He + H). The probability of this reaction is an order of magnitude higher, and the average kinetic energy release is four times larger. These findings suggest the presence of a metastable electronically excited state; they are consistent with the proposed linear, centrosymmetric ion structure of He-H-H-He(+).
Ne2 [II (1/2)u]：辐射衰变和电子预解离。
DOI：
10.1039/b414368j
发表时间：
2005
期刊：
Physical chemistry chemical physics : PCCP
影响因子：
--
作者：
Matt-Leubner,Sara;Fedor,Juraj;Parajuli,Rajendra;Stamatovic,Aleksandar;Echt,Olof;Hagelberg,Frank;Głuch,Krzysztof;Probst,Michael;Scheier,Paul;Märk,TilmannD
通讯作者：
Märk,TilmannD