Gope Krishnendu, Luzon Itamar, Strasser Daniel
Institute of Chemistry, Hebrew University of Jerusalem, Jerusalem, Israel.
Phys Chem Chem Phys. 2019 Jul 7;21(25):13730-13737. doi: 10.1039/c9cp02908g. Epub 2019 Jun 17.
Triatomic Coulomb explosion dynamics are initiated by single-photon double ionization of NO with an ultrafast EUV pulse and are probed by delayed near-IR pulses. The triatomic benchmark system exhibits competing two- and three-body dissociation dynamics that are reflected in the time resolved branching ratios and in the co-linear three-body momentum correlation spectra. Both the N-NO and the NN-O bond dissociation channels result in vibrationally excited molecular products. Channel resolved kinetic energy release (KER) spectra exhibit shifts emerging at long probe delays of hundreds of femtoseconds. The asymptotic shifts, towards lower KER indicate that the long-range Coulomb repulsion is effectively screened at bond-distances above ∼16 Å, at which the Rydberg electron is localized on one of the dissociating fragments. Thus, revealing up to a 0.9 eV gap that develops between the molecular Rydberg ion state and its core at long bond distance.
三原子库仑爆炸动力学由超快极紫外脉冲对NO的单光子双电离引发，并由延迟近红外脉冲进行探测。这个三原子基准系统展现出相互竞争的二体和三体解离动力学，这反映在时间分辨分支比以及共线三体动量相关光谱中。N-NO和NN-O键解离通道都会产生振动激发的分子产物。通道分辨的动能释放（KER）光谱在数百飞秒的长探测延迟下出现了位移。向较低KER的渐近位移表明，在键距大于约16 Å时，远程库仑排斥被有效屏蔽，此时里德堡电子定域在其中一个解离碎片上。因此，揭示了在长键距下分子里德堡离子态与其核心之间形成的高达0.9 eV的能隙。
