氢原子掠散射氧化NiAl(110)面负离子形成  

Negative ions formation in grazing scattering of hydrogen atoms from an oxidized NiAl(110) surface

作　　者：张瑞琦 汪建业[1] 周虎[3] ZHANG Rui-qi;WANG Jian-ye;ZHOU Hu(Institute of Nuclear Energy Safety Technology,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,China;University of Science and Technology of China,Hefei 230026,China;School of Nuclear Science and Technology,Lanzhou University,Lanzhou 730000,China)

机构地区：[1]中国科学院合肥物质科学研究院,核能安全技术研究所,合肥230031 [2]中国科学技术大学,合肥230026 [3]兰州大学核科学与技术学院,兰州730000

出　　处：《兰州大学学报（自然科学版）》2021年第3期423-426,共4页Journal of Lanzhou University(Natural Sciences)

基　　金：国家自然科学基金项目(11775103)。

摘　　要：对于掠入射条件下原子从绝缘体表面散射,散射粒子束中高比例的负离子产额被观测到.Demkov模型定量解释了在低速负离子形成阈值附近的负离子产额的速度依赖关系,由于该模型未考虑任何电子损失行为,导致在较高速度时,不能解释形成负离子产额的下降趋势.提出了改进模型,考虑了电子隧穿通过排斥库伦位垒的量子隧穿机制,以及表面激子形成的贡献,能够描述氢负离子在氧化NiAl(110)表面的电子脱附行为,在整个速度范围内计算结果与实验数据符合较好.Atoms are scattered from the surface of an insulator under a grazing incidence and a high proportion of negative ion yield in the scattered beam is observed.The Demkov model quantitatively accounts for the velocity dependence of negative ion yields near the low velocity threshold negative ion formation.However,the model does not consider any electron loss behavior,thus making it unable to explain the fall of the formed negative ion yields at a higher velocity.We proposed an improved model,which considered the quantum tunneling mechanism of electron tunneling by repelling the Coulomb barrier and the contribution of surface exciton formation,and could thus describe the negative hydride ion detachment behavior on the surface of oxidized NiAl(110)and calculate the results in good agreement with the experimental data in the overall velocity range.

关 键 词：负离子 表面散射 激子 电子脱附 

分 类 号：O562.4[理学—原子与分子物理]