Highly efficient double ionization of mixed alkali dimers by intermolecular Coulombic decay
Highly efficient double ionization of mixed alkali dimers by intermolecular Coulombic decay
复制标题
DOI：
10.1038/s41567-018-0376-5
复制
发表时间：
2019-03-01
期刊：
影响因子：
19.6
通讯作者：
Mudrich, M.
中科院分区：
文献类型：
--
作者：
LaForge, A. C.;Shcherbinin, M.;Mudrich, M.
与纯分子系统不同的是，电子动力学只通过分子内过程进行，弱结合的络合物，如He液滴，提供了一个局部激发可以与邻近的嵌入分子相互作用的环境，从而产生新的分子间驰豫机制。在这里，我们报道了一种新的衰变机制，通过分子间能量转移导致附着在He液滴上的碱性二聚体的双电离。从电子光谱来看，这一过程类似于在双俄歇衰变和单光子双电离(1，2)中观察到的众所周知的抖动机制，但在这种情况下，该过程占主导地位，发生的效率等于或大于通过能量转移进行的单电离。虽然附着在He液滴上的碱性二聚体是一个模型，但其衰变机制适用于任何一个组分的激发能超过另一个相邻分子的双电离势的体系。这一过程尤其与生物系统有关，在生物系统中，已知自由基和慢电子会造成辐射损害(3)。
As opposed to purely molecular systems where electron dynamics proceed only through intramolecular processes, weakly bound complexes such as He droplets offer an environment where local excitations can interact with neighbouring embedded molecules leading to new intermolecular relaxation mechanisms. Here, we report on a new decay mechanism leading to the double ionization of alkali dimers attached to He droplets by intermolecular energy transfer. From the electron spectra, the process is similar to the well-known shake-off mechanism observed in double Auger decay and single-photon double ionization(1,2), however, in this case, the process is dominant, occurring with efficiencies equal to, or greater than, single ionization by energy transfer. Although an alkali dimer attached to a He droplet is a model case, the decay mechanism is relevant for any system where the excitation energy of one constituent exceeds the double ionization potential of another neighbouring molecule. The process is, in particular, relevant for biological systems, where radicals and slow electrons are known to cause radiation damage(3).