School of Physics, Xi'an Jiaotong University, Xi'an 710049, China.
Institute of Applied Physics and Computational Mathematics, Beijing 100088, China.
Phys Rev Lett. 2023 Jun 9;130(23):233001. doi: 10.1103/PhysRevLett.130.233001.
We investigate the intermolecular nonradiative charge transfer process in a double hydrogen-bonded formic acid (FA) dimer, initiated by electron-collision induced double ionization of one FA molecule. Through fragment ions and electron coincident momentum measurements and ab initio calculations, we obtain direct evidence that electron transfer from the neighboring FA molecule to fill one of the two vacancies occurs by a potential energy curve crossing of FA^{++}+FA with FA^{+}+FA^{+*} curves, forming an electronic excited state of dicationic dimers. This process causes the breaking of two hydrogen bonds and subsequently the cleavage of C─H and C─O covalent bonds in the dimers, which is expected to be a general phenomenon occurring in molecular complexes and can have important implications for radiation damage to biological matter.
我们研究了由一个 FA 分子的电子碰撞诱导双电离引发的双氢键甲酸（FA）二聚体中的分子间非辐射电荷转移过程。通过碎片离子和电子符合动量测量和从头算计算，我们获得了直接证据，表明电子从相邻的 FA 分子转移以填充两个空位之一是通过 FA^{++}+FA 与 FA^{+}+FA^{+*}曲线的势能曲线交叉发生的，形成了二聚阳离子的电子激发态。这个过程导致两个氢键的断裂，随后二聚体中 C─H 和 C─O 共价键的断裂，这预计是在分子复合物中普遍存在的现象，并可能对生物物质的辐射损伤有重要影响。
