X-ray emission following charge exchange between slow highly charged ions and atomic H and its Astronomical application

Subjects: Physics >> Atomic and Molecular Physics submitted time 2023-12-03

Chijun Zhang Tian Liao Ruitian Zhang

Abstract： Experimental and theoretical research on X-ray emissions following charge exchange between slow highly charged ions and atomic Hydrogen supply vital atomic data in the study of diagnosing and simulating plasmas in non-equilibrium astrophysical environment. In the present paper, employing the semiclassical multi-channel Landau-Zener (MCLZ) method, we calculated the total cross-section of bare and hydrogenic C, N, O ions charge exchange with hydrogen atoms, and compared it with previously reported experimental results. In C5 + H collision, theoretically calculated cross-sections have large differences with experimental cross-sections. We also compared state-selective cross-sections calculated by classical MCLZ and quantum-mechanical molecular orbital close-coupling(QMOCC) methods in the solar wind ion velocity (or energy) range. For capture to n = 3 shell, MCLZ calculated state-selective cross-section increase with collision energy increasing; For capture to n = 4 shell, MCLZ calculated state-selective cross-section decrease with collision energy increasing; It is lower than two magnitudes as QMOCC method calculated cross-section. Finally, using the Kronos program package developed in the astrophysical field, we calculated the X-ray emission spectrum, line ratio, and hardness ratio of charge exchange of 1000 eV/u O8 by means of recommended cross-section by Janev, and contrast with the MCLZ method calculated results. We consider that the MCLZ calculation has a large uncertainty, which could affect the accuracy of the astrophysical environment simulation. It is required for developing a more accurate full quantum theory.

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