甲烷分子电子碰撞电离和解离的实验研究

本文利用反应显微成像技术(reaction microscope)研究了54 eV电子入射甲烷分子导致的电离解离过程,详细分析了电离解离产生的CH⁺₂,CH⁺,C⁺离子碎片的动能分布情况.实验结果表明,该入射能量下产生CH⁺₂,CH⁺,C⁺离子碎片主要贡献来自2a₁内价轨道电子的直接电离过程产生的离子态(2a<关键词：反应显微成像谱仪电离解离能量沉积动能分布

Dissociative ionization of methane by 54 eV electron impact

The dissociative ionization process of methane induced by 54eV electron impact is investigated using an advanced reaction microscope. In the present paper, our attention is specially paid to the kinetic energy distributions of the CH⁺₂,CH⁺ and C⁺ fragments. Energy deposition spectra are presented for these fragments of different kinetic energies. It is shown that the dissociations from the (2a₁) ^-1 and (1t₂) ^-2(3a₁) states of CH⁺₄ are the dominant contributions of the CH⁺₂, CH⁺ and C⁺ fragments. The kinetic energy of fragment is sensitive to the electronic state of its parent ion. Fragment ions with kinetic energies lower than 0.1 eV are mainly from the dissociation of (2a₁) ^-1 state, and partly from the dissociation of (1t₂) ^-2(3a₁) state; the ions with energies between 0.1 eV and 0.3 eV are contrituted equally by the two states; the ions with energies higher than 0.4 eV are formed dominantly from the dissociation of (1t₂) ^-2(3a₁) state.