Atomic and Molecular Collisions Laboratory, CEFITEC, Department of Physics, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.
Department of Materials and Life Sciences, Sophia University, Tokyo 102-8554, Japan.
J Phys Chem Lett. 2023 Jun 15;14(23):5362-5369. doi: 10.1021/acs.jpclett.3c00786. Epub 2023 Jun 5.
HO/DO negative ion time-of-flight mass spectra from electron transfer processes at different collision energies with neutral potassium yield OH/OD, O, and H/D. The branching ratios show a relevant energy dependence with an important isotope effect in DO. Electronic state spectroscopy of water has been further investigated by recording potassium cation energy loss spectra in the forward scattering direction at an impact energy of 205 eV (lab frame), with quantum chemical calculations for the lowest-lying unoccupied molecular orbitals in the presence of a potassium atom supporting most of the experimental findings. The DO-D bond dissociation energy has been determined for the first time to be 5.41 ± 0.10 eV. The collision dynamics revealed the character of the singly excited (1b) molecular orbital and doubly excited states in such K-HO and K-DO collisions.
HO/DO 负离子的飞行时间质谱，来自中性钾在不同碰撞能下的电子转移过程，产生 OH/OD、O 和 H/D。分支比显示出与碰撞能相关的显著同位素效应。通过在 205 eV（实验室框架）的冲击能下，在向前散射方向记录钾阳离子能量损失谱，进一步研究了水的电子态光谱，并用量子化学计算对存在钾原子时最低占据分子轨道进行了计算，这支持了大多数实验结果。首次确定 DO-D 键的离解能为 5.41 ± 0.10 eV。碰撞动力学揭示了在 K-HO 和 K-DO 碰撞中，单激发（1b）分子轨道和双激发态的特征。
