Photodissociation of Trapped Metastable Multiply Charged Anions: A Routine Electronic Spectroscopy of Isolated Large Molecules?
Photodissociation of Trapped Metastable Multiply Charged Anions: A Routine Electronic Spectroscopy of Isolated Large Molecules?
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被捕获的亚稳态多电荷阴离子的光解：孤立大分子的常规电子光谱？
DOI：
10.1021/jp049261b
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发表时间：
2004
影响因子：
2.9
通讯作者：
M. Kappes
中科院分区：
文献类型：
--
作者：
M. Kordel;D. Schooss;S. Gilb;Martine N. Blom;O. Hampe;M. Kappes
在傅里叶变换离子回旋共振（FT-ICR）质谱仪中捕获的四阴离子酞菁在光激发下发生电子损失和解离。通过在355 nm和570和695 nm之间照射覆盖酞菁的Q带区域进行实验。激光能量密度的依赖性显示了一个双光子过程作为所观察到的衰变的基本吸收规律，这对应于一个意想不到的低动力学位移给定的69原子大小的这个分子和预期的衰变通道的活化能。我们将这种效应归因于这些4倍负电荷离子的显著电子亚稳性。电子激发不仅与热电离，但也与相应的隧道自动脱离率的增加。
Electron loss and dissociation occur upon optical excitation of tetraanionic phthalocyanines trapped in a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. Experiments were carried out by irradiating at 355 nm and between 570 and 695 nm covering the Q band region of phthalocyanines. Laser fluence dependencies show a two-photon-process as the underlying absorption law for the observed decay which corresponds to an unexpectedly low kinetic shift given the 69-atom-size of this molecule and the activation energies expected for the decay channels. We assign this effect to the pronounced electronic metastability of these 4-fold negatively charged ions. Electronic excitation is associated not only with thermal ionization but also with a corresponding increase in the tunneling autodetachment rate.