近日，北京应用物理与计算数学研究所刘玲团队研究了C³⁺离子与H和D低能碰撞中的电荷交换过程。该项研究成果发表在2025年10月30日出版的《物理评论A》杂志上。

采用全量子力学分子轨道紧耦合方法，研究组在10^-5–10 keV/u的宽能区范围内研究了C³⁺(1s²2s²S)离子与氢、氘原子碰撞中的电荷交换过程。通过从头算多参考态单双激发组态相互作用方法计算了所需分子势能曲线与耦合矩阵元，并采用包含所有活性电子的大基组以获得精确的渐近能级差。

研究组获得了总体与态选择电子俘获截面及速率系数，与实验数据吻合良好。研究发现总截面随碰撞能降低而增大，在0.1 keV/u以下能区以2s3s³S和2p²¹S通道为主导；当碰撞能高于0.1 keV/u时，因高能态贡献使总截面随能量上升而增大。总截面在不同能区呈现复杂的振荡行为：在1 eV/u以下能区，密集振荡结构源于入射通道中的准束缚振转态，该能区氢/氘靶的同位素效应显著；10 eV/u附近的振荡模式源自2p²¹S通道与入射通道的干涉；而在0.5–3.0 keV/u能区，振荡结构主要源于C²⁺离子三重态与单重态中2s3s、2s3p、2p3s和2s4s态的多通道干涉。由于三重态与单重态在2p²和2s3s电子组态上的电子俘获存在显著差异，观测到三重态与单重态电子俘获截面之比偏离自旋统计规则。

附：英文原文

Title: Charge-exchange processes in low-energy collisions of C3+ ions with H and D

Author: Yun-Yu Wu, Yu Wang, Ya-Dong Liu, Min-Xuan Ma, Xiao-He Lin, Chun-Hua Liu, Ling Liu, Yong Wu, Jian-Guo Wang

Issue&Volume: 2025/10/30

Abstract: Charge-exchange processes in collisions of C3+(1s22s2S) ions with hydrogen and deuterium atoms are investigated employing the full quantum-mechanical molecular-orbital close-coupling method in the large energy range of 105–10 keV/u. The required molecular potential curves and coupling matrix elements are calculated by the ab initio multireference single- and double-excitation configuration interaction method, and large basis sets with full active electrons are employed to obtain accurate asymptotic energy differences. Total and state-selective electron capture cross sections and rate coefficients are obtained and show satisfactory agreement with the experimental data. Total cross sections are found to increase as the collision energy decreases with the dominance of 2s3s 3S  and 2p21S  channels in the energy region below 0.1 keV/u, and then increase as the collision energy increases above 0.1 keV/u due to the contributions of higher states. Meanwhile, the total cross sections exhibit complex oscillatory behaviors in various energy regions. Below 1 eV/u, the dense oscillatory structures arise from quasibound vibrotational states in the entrance channel, and the isotope effect for hydrogen and deuterium targets is noticeable in this energy region. Around 10 eV/u, the oscillatory patterns originate from the interference between the 2p21S  channel and the entrance channel, while in the 0.5–3.0 keV/u energy range, the oscillatory structures primarily arise from the multichannel interference among the 23, 2s3p, 2p3s, and 2s4s states in both the triplet and singlet states of C2+ ions. The ratios of cross sections for electron capture to the triplet- and singlet-state manifolds are found to deviate from the spin-statistics rule bacause of the significant differences in electron capture to 2p2 and 2s3s electronic configurations between triplet and singlet states.

DOI: 10.1103/1893-sjqz

Source: https://journals.aps.org/pra/abstract/10.1103/1893-sjqz