2025-03-27 中国科学院（CAS）
＜関連情報＞
- https://english.cas.cn/newsroom/research_news/phys/202503/t20250326_908780.shtml
- https://iopscience.iop.org/article/10.3847/1538-4365/adb72a
N5+とHeの電荷交換における衝突エネルギー敏感な状態選択性と線比 Collision-energy-sensitive State Selectivity and Line Ratios in Charge Exchange between N5+ and He
X. B. Zhu, R. T. Zhang, C. J. Zhang, S. Mitrani, L. Gu, Y. Gao, S. F. Zhang, and X. Ma
The Astrophysical Journal Supplement Series Published: 2025 March 18
DOI:10.3847/1538-4365/adb72a
Abstract
Astrophysical charge-exchange modeling depends on an accurate database of state-resolved and velocity-dependent cross sections. The cross sections, resolved by the quantum state with principal n and orbital angular momentum ℓ, are pivotal in determining X-ray and extreme ultraviolet (EUV) emissions following charge exchange between highly charged ions and neutrals. However, the current cross-sectional data are primarily theoretically derived and have undergone limited experimental validation. Using high-resolution cold-target recoil-ion momentum spectroscopy, we conduct an experimental study on state-selective cross sections of charge exchange between 5.36 and 75 keV u−1 N5+ ions and He. Evidently, at low collision energies electrons are mainly captured in the n = 3 state of N4+ ions, and higher n capture competitively comes into play as the increase of collision energy. The relative cross sections are reported for state-selective electron capture into 2s, 2p, 3s, 3p, 3d, 4ℓ, 5ℓ, and n ≥ 6 Rydberg series of N4+(1s2nl) ions. The ℓ distributions commonly used in astrophysical literature are evaluated by comparing them to the measured ℓ-resolved state-selective cross sections for the dominant n = 3 capture, which allows us to experimentally derive the collision-energy-dependent EUV line ratios.
