Iskandar W, Matsumoto J, Leredde A, Fléchard X, Gervais B, Guillous S, Hennecart D, Méry A, Rangama J, Zhou C L, Shiromaru H, Cassimi A
CIMAP, CEA-CNRS-ENSICAEN, BP 5133, F-14070 Caen Cedex 5, France.
Department of Chemistry, Tokyo Metropolitan University, 1-1 Minamiosawa, Hachiouji-shi, Tokyo 192-0397, Japan.
Phys Rev Lett. 2014 Oct 3;113(14):143201. doi: 10.1103/PhysRevLett.113.143201. Epub 2014 Oct 2.
Electron capture processes for low energy Ar(9+) ions colliding with Ar(2) dimer targets are investigated, focusing attention on charge sharing between the two Ar atoms as a function of the molecular orientation and the impact parameter. A preference for charge-asymmetric dissociation channels is observed, with a strong correlation between the projectile scattering angle and the molecular ion orientation. The measurements here provide clear evidence that projectiles distinguish each atom in the target and that electron capture from near-site atoms is favored. Monte Carlo calculations based on the classical over-the-barrier model, with dimer targets represented as two independent atoms, are compared to the data. They give new insight into the dynamics of the collision by providing, for the different electron capture channels, the two-dimensional probability maps p(b), where b is the impact parameter vector in the molecular frame.
研究了低能Ar(9+)离子与Ar(2)二聚体靶碰撞的电子俘获过程，重点关注两个Ar原子之间的电荷共享作为分子取向和碰撞参数的函数。观察到电荷不对称解离通道的偏好，弹丸散射角与分子离子取向之间存在强相关性。这里的测量提供了明确的证据，表明弹丸能够区分靶中的每个原子，并且有利于从近位原子捕获电子。将基于经典势垒模型的蒙特卡罗计算与数据进行了比较，其中二聚体靶表示为两个独立的原子。通过为不同的电子俘获通道提供二维概率图p(b)，其中b是分子框架中的碰撞参数矢量，它们为碰撞动力学提供了新的见解。
