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23 12, 2023
Scientists Observe a Novel Molecular Ionization Dissociation Pathway Induced by Interatomic Coulombic Decay
A research group led by Prof. MA Xinwen at the Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS), has observed a novel molecular ionization dissociation pathway triggered by Interatomic Coulombic Decay (ICD). The study verifies the theoretical prediction and has potential application in developing new radiotherapy.
The results were published in Physical Review Letterson December 18.
ICD is an important energy transfer process, which generally exists in weakly bound systems, such as the van der Waals cluster, the hydrogen bond cluster, and the solution. It has been widely accepted that ICD-induced molecular fragmentation occurs through a two-step process, involving ICD as the first step and dissociative-electron-attachment (DEA) as the second step. However, some theoretical calculations recently proposed a one-step mechanism, where ICD directly causes the dissociation of a molecule. If this mechanism is validated, the traditional view of ICD will be changed.
Selecting the ArCH4 dimer as a prototype system, the researchers at IMP performed an experiment by employing a transversal reaction microscope.
Besides the well-known ionization pathways induced by ICD (channel A), a coincident island (channel B) representing the Ar+/CH3+ ion pair was observed, which demonstrates CH4 ionization dissociation induced by ICD. The yield of channel B is 1.7 times larger than that of channel A, indicating it is of high efficiency.
Via this new pathway, it will be possible to construct an antenna-receiver complex, and to enhance the cross-section of the molecular ionization dissociation by at least one order.
Furthermore, this finding offers a novel approach to directly break covalent bonds in DNA molecules, surpassing the processes involving DEA. It has potential applications in developing new radiotherapy.
This work was supported by the National Key R&D Program of China, the Strategic Priority Research Program of CAS, and the National Natural Science Foundation of China.
Figure. Two-dimensional TOF correlation map. The arrow marked with A is the ionization pathway inducing the Ar+/CH4+ ion pair, while the arrow marked with B is the ionization dissociation pathway inducing the Ar+/CH3+ ion pair. (Image by YAN Shuncheng)
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Institute of Modern Physics
Email: fangliu@impcas.ac.cn
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